My Stepsister is My Ex-Girlfriend - Volume 4 - Chapter 1

A Day in the Life of the Future Couple

Night Chat

This happened back during the summer vacation of eighth grade. After finishing dinner, I went back to my room, flopped on my bed, and heaved a long sigh as I recollected my first date.

I’d gone to the festival with Irido-kun in my yukata. That’s literally exactly what happened, but somehow, I still couldn’t wrap my head around the reality of it all. How could I?

It hadn’t even been ten days since I became able to even talk to him. So how had I managed to go on a date with him to a festival already? Was this a result of some stochastic variable—a lucky roll of the dice?! Plus...

“Heh heh...” My face pressed against my pillow, a gross smile unbefitting of me creeping across it.

After I’d gotten lost, I’d called Irido-kun and sobbed until he found me. My usual negative thinking made me sure that he would hate me after all that, but what did he say? “You can bother me all you like.”

Oh my god, I love him. I love him so, so, so, so much! I excitedly kicked my legs against the bed. People really could fall hard for someone in a short period of time. Until just a little bit ago, I’d seen him as my academic rival. But now, whenever I thought about him, my heart would pound, my knees would go weak, and my mind would go blank. I want to see him. I want to talk to him.

We wouldn’t be able to meet at the library for two more days because he apparently had other obligations. I can see him again in just a couple days... Just as I thought that, my eyes landed on my phone next to my pillow. Then, as if a light bulb lit up in my brain... If I really want to talk to him, then what’s stopping me? I have his number.

But then I got worried. Is it okay for me to call him? Maybe I’ll just be a bother. It’s already nighttime, so calling him might be annoying. But then I remembered our date. I was a lot more annoying back then and he forgave me. So it should be okay...right? It’s just a phone call, after all...

I hesitantly reached for my phone, but at that exact moment, before my fingers had even made contact, it began to ring.

“Wah—”

I hadn’t customized anything yet, so it was still the default ringtone. I grabbed my phone in a panic to see who could be calling me.

“I-Irido-kun?!” Huh? Why? Why is he calling me at this exact moment? Can he read my mind?!

How was it possible that the exact person I wanted to talk with had called me at the exact time I was about to call him? Th-This must have been the stochastic variable at play again. God had personally seen to it that the coin landed on heads every time. What would happen when the other shoe dropped? I was terrified to even think about it.

Either way, right now, I need to answer the phone. He might hang up if I take too long to answer!

“HEL— Hello?” I was too excited; the first syllable practically exploded out of my mouth. Fortunately, I was able to self-correct so that in the end, I only sounded like I’d been startled awake. Agh, why am I so bad at controlling my volume? I’m so useless!

“Hel...lo?” The quality of his voice wasn’t great. Is his connection bad? “Can...you talk?”

“Y-Yeah! I can talk. I’m completely free! I have absolutely nothing to do!” I got the feeling I was kind of overdoing it. Calm down! In an attempt to hide how desperate I was, I quickly tried to move the conversation forward. “Wh-What’s up? D-Do you need something?”

“No... Nothing in particular.”

“Oh, I see...”

“Yeah, I just kinda...wanted to talk with you, Ayai.”

“Hyeh?!” I was so surprised by his words that a strange sound escaped my lips. H-He wants to t-talk with m-me? Me?! Why?! For what reason?! “O-Oh, me...me too.” Don’t lose yourself. Push on the gas! “I... I was thinking about calling you too, Irido-kun.” I did it! I said it! Go me!

“Oh. Then...perfect timing, I guess.”

“Y-Yeah, totally! Ehe heh heh.”

It was late at night, I was alone in my room, and yet...I could hear Irido-kun’s breathing from the phone as if he were right next to me... Was it really okay for me to be this happy?

After that, we had a long conversation about a few topics: what books we were reading and new arrivals at the library. Due to our lack of friends, we couldn’t really talk about anything else, but even so, our conversation never dried up.

“I really think that the period of time in which mystery authors try to outdo the complexity of each other’s gimmicks is over.”

“Agreed. Nowadays, they focus more on the logic and wits of the characters. They also try to make the settings more unique—”

Just as he said that, I heard the sound of trees rustling in the distance, prompting me to look out the window, but I lived in an apartment complex so I couldn’t exactly see any trees.

“Is it windy outside?” I asked.

“Hm... Yeah, a little.” I felt like his answer was a little weird, but I didn’t have the time to ask anything because in the next moment...

“Yume? You up? I’m coming in!”

“Hyeh?!” The door to my bedroom opened and in came my mom. I panicked and hid under my covers, clutching my phone against my chest to hide it. “Wh-What do you need?”

“I’m here to take your garbage.”

“You could at least knock!”

“Why? You’ve never told me to before. Are you in your rebellious phase?”

Th-That was close. If she found out I was talking with a boy at night, she’d tease me for the rest of my life. She collected the trash out of my wastebasket and looked like she was going to leave, but...

“Hm? What’s this tissue doing over here?” she said, reaching under my desk to pick up a used tissue...while I was still on the phone with Irido-kun. “How many times do I have to tell you to properly throw out your trash? I bet you were lazing around on your bed when you tried to throw this out. Why would you do that when you have no aim?”

“Ah! Ahhhh!” How could she say that?! Irido-kun might be listening! I stuffed my phone under the covers and jumped off my bed.

“I wasn’t lazing or anything! That tissue just fell out by accident!”

“Hm, I don’t know, Yume. You can be a slob. Remember in the bathroom, you left a—”

“Shut up!!! If you’re done, get out of my room!!!”

“You really are in your rebellious phase! I never thought this day would come!”

I pushed my mom out of my room, thumping her with my fists, before she could bring up the worst possible thing for Irido-kun to hear. I quickly returned to my bed and fearfully pressed the phone against my ear.

“S-Sorry... My mom came...”

“Don’t worry about it.”

“Did... Did you hear anything?” If he had, that’d probably spell the end for our relationship. I loved my mom, but if she was the cause of our breakup, I’d probably hate her forever. I might declare my rebellious phase to her face, in fact. But as I steeled myself to hear the answer I dreaded, I was met with an unexpected response.

“Nope... I didn’t hear a thing.”

“O-Oh...” Thank god! But just as I heaved a sigh of relief, he continued.

“I think I heard some kind of rhythmic beating noise in the beginning.”

“Huh?” Then I remembered what I’d done. I’d panicked and hidden under my covers, holding my phone against my chest. I’d held my phone against my chest. Against my chest... Did that mean that the microphone had been pressed right up next to my heart? Did that mean I’d sent him sounds of my beating heart in real time?! “A-Ah... Ahhhhhh!!!”

“W-Wait, it’s fine! If anything, I should apologize for listening!”

“Y-You weren’t bothered by it...?”

“Well... It was like I could tell you were alive. I could feel your existence. Thinking about it like that made me feel relieved. Oh god, I must sound like such a creep. I’m sorry!”

I groaned—not because I thought he was a creep, but because I was so embarrassed! How could having your heartbeat heard be so embarrassing?! It was even worse than someone seeing your panties. It was like the deepest parts of me had been looked into.

“Y-You didn’t think it was weird...?”

“Nope. If anything, I was worried, because it was a little fast.”

“Ahh...”

“B-But it’s completely normal in that situation! Completely normal! Not weird at all!”

Wow, he’s comforting me. He’s so nice. I love him so much!

“You’re doing your best, Ayai. You should be more confident,” he suddenly whispered.

It caught me so off guard that I dove under my covers. In the darkness, I could only hear the sound of Irido-kun’s breathing. Maybe that’s why my next words flowed out so naturally.

“Could you...say that again?”

“You’re doing your best.”

“Mmhmm.”

“I’m proud of you.”

“Mmhmm!”

“Also... Huh, this is becoming like one of those weird motivational videos.”

“Heh heh...” As I giggled, I could hear Irido-kun laughing with me.

He wasn’t anywhere near me, and I couldn’t see him, but it felt like we were right next to each other.

“Hey, Ayai?”

“Hm? What’s the matter?” Why did he say my name out of the blue?

“Never mind...” It sounded like he was hesitating. “My phone’s about to die.”

“Oh, I see...” Our dreamlike time together was about to end. I really didn’t want it to, but I couldn’t let myself show that. “I’m going to do my best, Irido-kun. Would it be okay if...we talked again sometime?”

“Yeah, of course. I’m pretty sure I’ll be able to go to the library the day after tomorrow.”

“I can’t wait. I’ll be there.”

“Okay then...”

“Yeah...”

“Night...”

“Talk to you later...”

There was a strange reluctant silence for a few seconds before we hung up. I looked at my phone in a daze and saw that our call had lasted for forty-three minutes and forty-five seconds on August 12th at 7:57 pm.

I hope he comes to the library early... I felt so much more strongly than I had forty-three minutes prior. He could’ve charged his phone while we talked...

The Ex-Couple Wants Stimulation

“Don’t call me ‘hot.’”

“Mizuto-kun, do you know where the bookmark that came with this is?” Yume asked.

It was the afternoon, and we were currently in the living room, reading. I reluctantly stopped and looked up to see that she was holding the book that I’d lent her. What bookmark?

“Oh... Yeah, I guess there was a bookmark in there. It’s probably somewhere on my desk.”

“It’s somewhere in that mess? Why didn’t you just leave it in the book?”

“My bad. I didn’t use it at all. I’ll look for it later, so—”

“Not later, now! You’re gonna forget about it otherwise.”

“Ugh. I don’t wanna.”

“Huh? Be responsible. Be more thoughtful about the condition of the things you lend out!”

“Yeah, yeah.” I let out a sigh and got up off the couch. You’re right. I get it already.

I decided to find it quickly and get back to reading, but just as I was about to leave the living room, I felt two pairs of eyes on the two of us. Yuni-san and dad were home due to a rare day off and were sitting at the dining table, holding back laughter.

“Is...something wrong?” Yume asked.

Yuni-san snorted a little before answering. “Well, it’s just...”

“Yeah, I completely understand.” Dad nodded, his shoulders shaking with laughter.

Yume and I tilted our heads in confusion. We had no idea what exactly was so funny about the current situation.

Yuni-san laughed even harder. “The two of you are acting like a couple getting out of your honeymoon phase.”

The two of us shivered a little. Yuni-san had been referring to the part of a relationship when you’ve been together for long enough that you get stuck in a rut and start focusing on the parts of your partner that you can’t stand. Depending on the couple, you may end up breaking up. Every couple, married or not, dreads this.

“I’m surprised,” Yume said, firmly pressing her cushion against the floor.

We were currently holding an emergency meeting in her room to discuss the unexpected situation that’d arisen.

“I’d thought that getting used to living here would’ve eliminated any unnatural behaviors. I can’t believe it actually brought up new problems,” Yume lamented.

“Thinking about what they said... Our behavior really was like a legit couple. I doubt that anyone pretending would give off the same vibes.”

“Only we’re not a real couple anymore!”

“Yeah, exactly. So it’s a problem that we’re being seen as one.”

Of course, dad and Yuni-san had just been joking around. They had no clue that we used to date. I couldn’t deny that after living together for four months, I’d become a little lax and unguarded. Our conversation in the living room hadn’t exactly been one of two stepsiblings getting along, but of a couple getting out of their honeymoon phase, or maybe even of real siblings.

It was completely possible for someone to find the way we were acting odd for people who’d supposedly only just met each other.

“It seems there’s a need to recall how we felt when we first moved in together,” Yume said with a sour look on her face. “We need to bring back the tenseness we had four months ago.”

“Well, whether we’ll be able to fool our parents or not, it doesn’t change the fact that you’ve been letting your guard down in general. You call me at night like it’s the most natural thing in the world. And you walk around like you own the place in skimpy clothes.”

“Th-They’re not skimpy! I’m dressed more lightly because it’s summer!”

Yume gripped the cushion against her body as if to cover herself while backing away from me. She was currently wearing an oversized shirt, short culottes, and knee socks. Despite making a big fuss about not showing off her bare legs in public, half of her thighs were basically on full display. Plus, the bagginess of her shirt made it so that if she bent over, her cleavage could easily be seen...not that I was looking. I wasn’t.

Plus, she was wearing glasses. She usually had contacts in, but since she wasn’t going out as much, she’d gotten lazy and wore glasses most of the time. Her outfit really reminded me of how she was in middle school, and that was not great for my mental health.

“You’re giving me a weird look.” She glared at me through the lenses of her glasses. She lifted her knees, flashing her thighs—probably on purpose—but I quickly looked away.

“Anyway, you weren’t so chill about your outfit in front of me four months ago. It just kinda seems like you’ve slipped back into how you were in middle school...”

“Argh, fine! Shut up already! We just have to find a way to get over this ‘post-honeymoon phase’ thing, right?!”

“Have you been hearing what I’ve been saying? We’re not dating. There is no ‘post-honeymoon phase’ thing. Or wait... Could we use that as a model case?”

“A what?”

“We’ll use the method that couples use to overcome this stage in their relationships as a way to get our tenseness back.”

“Oh, okay... You have a point. That may be a good place to start since we don’t know what to do,” Yume mumbled while pressing her thumb against her bottom lip. “But how should we go about it?”

“...”

“Why aren’t you saying anything?”

“I was just remembering that we broke up precisely because we couldn’t get past that stage in our relationship.”

“True...”

We’d fit the description of this stage perfectly. We’d found parts of each other that we hated and couldn’t stop noticing them. We hadn’t had a name for this back in the day, but last summer was precisely our post-honeymoon phase. It had been so uneventful, though, that I had a hard time remembering it.

“We’ll just have to borrow someone else’s wisdom,” she finally said.

“Whose?”

“The internet’s.”

“Wait... Whenever you had a problem with me, did you always go straight to the internet?”

“N-No! Of course not!”

Her shifting eyes told a different story. It all made sense now why she did weird things occasionally.

Yume pulled out her phone and said “overcome the post-honeymoon phase” into it, without even a shred of shame or embarrassment. But then again, we had nowhere else to turn, so neither of us had the luxury of feeling embarrassed.

“Let’s see...” she said, scrolling through the search results.

“Anything?”

“‘The post-honeymoon phase of a relationship typically starts after the first three months,’” she read out loud. That’s like right when you’re on the best terms with each other. “In order to overcome this stage, you must reconfirm your feelings for one another.’” She glanced at me through her glasses. What do you want me to say?

“I’m looking for a precise method, not pretentious statements.”

“There you go, making a beeline straight for the conclusion. I really hate that about you.”

“Oh wow, look, you are able to reconfirm your feelings! I think we just overcame our issues.”

“All we did was jump straight into ‘full-blown hatred’!” Yume sighed and looked back at her phone. “‘Method one: go on a date somewhere you don’t usually go.’”

I fell silent. A date? Here we were trying to make it so that dad and Yuni-san wouldn’t think of us as a couple, and yet the first method listed was a couple’s activity. Hm...

“What do you think?” Yume hugged her cushion against her, lay her legs to the side, and tilted her head while shooting me a glance. “Do you...want to go on a date?”

As much as I wanted to immediately laugh in her face, I agreed that we’d been a little too comfortable and lax recently.

“Where to? Where’s a place that we don’t usually go?”

“If we can’t go to a bookstore or the library then... Oh, I guess we only went there together in middle school.”

She had a point. We’d only ever really gone to those two places when we were dating. We hardly went there together now that we were living together. Then again, if we couldn’t go places that we usually went together, then...

“As long as we don’t stay home or go to school, we could go anywhere.”

“True...”

Since we were together at home and at school, it was completely possible that we’d gotten sick of each other. So maybe a change in scenery would work out.

“Hm... I see...” Yume mumbled to herself while swiping through her phone. You see what exactly? “This might be a good place.”

“Where?”

“If we can go anywhere aside from home or school, then I might have a good place. There’s something I’ve been wanting to buy, so you can tag along.”

“Something you want to buy?” Something other than a book? Can’t be summer clothes. It’s a little late for that.

Yume rested her chin on the top of the cushion she was holding and then bent her lips into a teasing smile. “A swimsuit.”

“I’m gonna stop by the bookstore.”

“Okay, don’t let the heat get to you.”

“Have fun.”

Neither dad nor Yuni-san had even an inkling that I was lying to them. It’s nice to be known as a person who only goes to a few places. I walked out of the house and made my way to the nearest corner of the street. It’s so friggin’ hot.

I looked up at the summer sky from the shade of a telephone pole while the sound of cicadas filled my ears. It felt like I was walking through a sauna. I could slowly feel myself being roasted alive. I needed to get to an air-conditioned store immediately.

I’d been told to leave first because she needed to change, but I was starting to think she wanted me to die from heatstroke.

“Hey. Are you still alive?”

Just as I began to think that, Yume popped out from around the corner. I was sure that she’d be wearing her usual “rich girl” clothes, but was completely taken aback by her actual outfit. I had no clue who she was at first.

If I was to put her look today into one word, it’d be “dynamic.” She was wearing a white shirt, jean shorts, and black thigh highs. It was a lot more revealing an outfit than I’d ever expected her to wear. The sleeves of her shirt barely covered her shoulders, and even the collar was deep, revealing her collarbone. Plus, her thighs were peeking out from the space between her shorts and thigh highs. The elastic band around them was slightly digging into her skin too.

However, the most dangerous part of her outfit to me was above her neck. I wasn’t sure whether she was wearing it as a way to keep the sun out, but she was wearing a wide brim hat, and her annoyingly long black hair was tied into low pigtails that hung down in front of her. That was already enough for me to remember the old Yume, but the killing blow was dealt by her glasses. She hadn’t taken them off since we were in her room.

“Heh heh.” Yume snickered like a kid who’d pulled off a prank. “‘Method two: try surprising them.’”

I scowled. I knew it was intentional. The two low pigtails that hung on her chest, along with her glasses—it was like she’d gone back to the Yume Ayai I’d known in middle school. But then again, looks can be deceiving, and that was definitely the case here.

“It’d be annoying if someone we know saw me, so I’m in disguise. Oh, right... Here.” Yume took out a blue baseball cap and presented it to me. Hm? “People know you now after you got first on the midterms. This’ll help keep you a little more incognito.”

“What am I, a celebrity?”

“If you’re good with people gossiping about us being on a date, feel free not to wear it.”

“Ugh...”

“Also...” Before I could respond, Yume took the hat and forced it onto my head. “The sun’s strong today. It’d be annoying if you got heatstroke.”

The girl I saw past the brim of the hat may have looked like the Yume Ayai that used to quietly follow me, but it wasn’t. Maybe it was because of how she’d grown or the different vibe she gave off with her new clothes...or maybe it was how she’d grown mentally. Either way, I had no intention of being her younger brother.

“Fine...”

“Good boy.”

I pulled the hat down to cover my eyes, and I thought we’d get going at this point, but Yume gave me a nervous look.

“What? Is there something else?”

“Well, uh... Yeah, there is one more thing...” She reached into her bag and brought out a certain item. Glasses. “I’m wearing a disguise, so... You should too.”

“No.”

“Why?! You’d look so hot!”

Don’t call me “hot.”

We walked ten or so minutes under the scorching sun before we decided to take a bus and get out of the heat. Even though there was a mall close to where we lived, it counted as a place that we’d normally go to, so it wouldn’t help us regain our tenseness. We needed to go somewhere new for that.

I had to focus on keeping our objective in mind, otherwise this excursion would end up being nothing more than me accompanying her on a shopping trip.

“So, why are you buying a swimsuit? Going to the beach or something?” I asked Yume as cool air blew across my body from the entrance of the mall.

“No,” she replied, patting down her neck with a handkerchief. “I thought Akatsuki-san would want to go to the beach, but she said she wants to avoid unsolicited advances. Plus, it’s kinda far.”

“Oh, I see...”

“Feel better now, sister lover?” Yume asked, leaning in front of me and gazing into my eyes.

For some reason, even though I didn’t react whatsoever, she giggled at me in a mocking manner. If I’m not careful, she might act high and mighty like this all day...

“Then why do you need a swimsuit?” I asked, trying to get back my momentum.

“Why?” Yume turned her gaze towards a store window. “Mineaki-ojisan said I might need one for Obon.”

“Dad did? For Obon... Oh, that’s more of a river than an ocean, though.”

I forgot that we were going to dad’s hometown to celebrate Obon this year. The house we were currently living in originally belonged to my grandfather. Unfortunately, I never met him, because he passed away before I was born.

Dad grew up in our house, but my grandmother lived somewhere else now. It was tradition to make a yearly visit to her during Obon. Naturally, we were going back this year too, especially now that our family of two had doubled.

My grandmother lived in the middle of nowhere. The only thing you could really amuse yourself with was playing in the river. It was like being in an unexplored region of the world.

That being said, I never did any of that stuff when I was growing up. I’d always make a beeline for the bookcase that my great-grandfather had left. Thinking back, this was probably what led me to reading all types of books instead of just a single genre.

The fact that the swimsuit she was buying was for that river connected the dots explaining why she came with me instead of Higashira or Minami-san. It would’ve been weird to invite people to go shopping for swimsuits if nobody but her needed one.

“I never thought I’d see the day that a high school girl would go out of her way to buy a new swimsuit to play in the river,” I said, fake-pitying her. “This is so sad. I might cry.”

“What’s wrong with rivers? They’re more fun than playing at the beach, which is way too crowded.”

“You’ve got a point, but you’re gonna be around family. You could just wear what you did last year instead of buying a brand-new one.”

“Are you making fun of me right now?” Yume leered at me, one arm wrapped around her belly.

“Huh?”

“You said that with my proportions from last year in mind, didn’t you?”

“...Oh.” My eyes inadvertently fell to her chest.

The white shirt she was wearing was puffed out in the chest area by mounds that hadn’t existed last year. Well, actually, it’s possible that her chest was already pretty big last summer. I wouldn’t know, though, since we’d had a fight before summer vacation started and didn’t really meet up.

“You’re looking too much...” Yume covered her chest with both arms and took a step back from me. “What’s up with you today? Are you okay? Are you in heat or something? Am I going to be safe trying on swimsuits? You won’t barge in and assault me?”

“Hell no. I’m not that ravenous a person. If I was, Higashira would never be safe with me.”

“I really hate to admit it, but you have a point...”

This was the first time I thought it was good that Higashira was as unguarded as she was.

“Either way, do your best not to stare at me with those lecherous eyes of yours. This isn’t your own personal peep show,” she said, returning to her original distance from me.

“A ‘show’? You in a swimsuit, a ‘show’? Wow, someone’s got a lot of confidence. I’m in awe at how much stock you put in yourself.”

She growled, angrily kicking my calf as we arrived at the store.

The first mannequin we saw had on a bikini that would only be appropriate on a Brazilian beach. There was no way that a thigh-highs-in-summer girl like Yume would wear it.

“Sorry to interrupt you while you’re so passionately gazing at it but... No. Not happening. My butt would hang out.”

“I know. Did I say I wanted you to wear that? We don’t know what kind of people would see you...”

“So it’s okay as long as nobody else is around?”

“I never said that.”

“Mm-hmm...”

“Why are you looking at me like that?”

“I was just thinking of a guy who complained about his girlfriend’s wonderful miniskirt.”

You still remember that? Sheesh...

“All right. Let’s get going and find a swimsuit that won’t arouse a certain someone’s gross possessiveness,” Yume said smugly.

I growled. I was this close to snapping and killing her on the spot, but before I could, a wild saleswoman appeared!

“Can I help you find something?” the saleswoman asked in a high-pitched voice, with a too-perfect smile plastered across her face as we entered the store. She reminded me of a robot programmed for customer service. Now I understand the uncanny valley hypothesis...

It might have been a little mean of me since she was just doing her job, but I could only see her as a monster in a dungeon. The only two options in my head were “fight” or “run.” Just as I was about to run, the girl next to me took a brave step towards the monster.

“Um, I’m looking for a swimsuit.”

“A bikini or a one-piece?”

“I think I’ll start with a one-piece...something that isn’t so revealing,” Yume said while shooting me a look.

The saleswoman didn’t waste a single second, immediately noticing the look Yume gave me. Her smile widened to the point that it was basically sparkling.

“You could go for a bikini too. There are skirt types that you could choose from. I’m sure it’ll put your boyfriend’s mind at ease.”

“Huh?”

Huh?

“U-Um, h-he’s not my—”

“Let’s get to looking then! May I ask for your sizes?”

“Huh? Wait. Sizes?” Yume’s face went red, her eyes flitting back and forth between me and the saleswoman, before whispering something into her ears.

The saleswoman nodded in understanding. “Got it! I’ll be right back,” she said before quickly disappearing into the back of the store.

Yume squeezed her red ears and exhaled. “I panicked. Who asks that kind of question?!”

“You can deal with store people now? I totally thought you were the type of person who’d choke.”

“I am. I am, but I did my best to work through it. Girls have to be conscious of their outfits, unlike a certain someone who puts absolutely no thought into what they have on.”

I had nothing I could say to that. All I could do was remember the first time I saw her in her street clothes. She’d barely ever hung out with friends, but despite that, she’d come in completely normal-looking clothes. I’d been surprised. She was working hard, even when I wasn’t looking. Not that it mattered anymo—

“Did you see? Did you?!”

“I did! So cute! Omigosh, high school couples are so bittersweet.”

Both of us fell silent. Can’t you salespeople talk somewhere where we can’t hear you?!

Thanks to that, we were left in a weird mood as we awkwardly gazed at the swimsuits on the racks and the passersby outside. After not too long, the saleswoman came back.

“Thank you for waiting! I brought you a swimsuit I think you’ll love! Let me know if you need a different size, okay? Oh, and if you’d like to try it on, please be sure to keep your underwear on,” she said, giving Yume a swimsuit while shooting me a weird look for some reason.

As she walked back to the register, I wondered what that look meant. It was as if she had been saying “good luck” or something. But why?

“Um... I guess I’ll try it on then.” Yume shot me a quick glance, holding the swimsuit against her body. “Do you...want to see it?”

“What’s wrong with the mirror in there?” Why would you want me to look?

“Th-This is the first time I’m buying a swimsuit. I need feedback!”

“So what? You’re gonna buy a swimsuit I like?”

“Well... O-Of course I’d buy the opposite of what you like. Why would I ever buy a swimsuit that you liked?!”

Oh, good. That’s a relief. “Okay... I guess it’d be awkward to stand around out here by myself anyway.”

“Exactly! You look so out of place.”

“Remind me, who dragged me here?”

Yume disappeared behind the curtains of one of the fitting rooms. I sat on a stool to wait for her. Swimsuits... We’d had swimming classes back in middle school, but our high school didn’t even have a pool. Thanks to that, I’d thought I’d never have to endure the sight of her in a swimsuit. But now...

From behind the curtains, I heard the sound of clothes rustling, being removed, and dropping to the floor. The sound of something being unzipped was especially loud and distinct. How could people feel comfortable taking off their clothes behind one thin piece of cloth like this? How could she feel comfortable when I was just on the other side?

I’d had good luck up until now because I’d never once run into Yume while she was in the middle of changing. Technically, I’d run into her when she was getting out of the bath, but that... What I accidentally saw back then—the pure white skin and curves... Stop. I erased the image forming in the back of my head. I’m not a horny middle schooler.

I’d been living with her for four months already. Her changing in front of me shouldn’t have bothered me in the slightest. As I tried to clear my mind, the sound of clothes rustling stopped, and about ten seconds later, Yume’s head poked out from behind the curtains, her glasses still on.

“What’s wrong?” I asked.

“Is... Is anyone around?” Yume asked, anxiously glancing around.

I could hear people in the mall, but there wasn’t anyone nearby except us... Well, I could feel the salespeople watching us, but that was about it. Besides, they weren’t positioned at an angle where they could see anything.

“Nope. But why does it matter? If you’re gonna wear that in public, you shouldn’t be embarrassed from just trying it on.”

“Sh-Shut up! I-I’ve never exposed my skin this much... In fact, thinking about it logically, I’m pretty much parading around in my underwear...”

“The longer you take, the higher the chance that someone comes is.”

“Don’t rush me! Do you want to see me in my swimsuit that bad?!”

“I’m the type who prefers to get the annoying stuff out of the way as fast as possible.”

“Y-You— I’m gonna make you cry!”

She flung the curtains open. My gaze shot to her porcelain thighs stretching out of the pure-white skirt she had on. Raising my eyes, I was met with her bare stomach. In the middle of her waist, which was almost worryingly thin, was her tiny belly button.

Looking up further, I saw a white piece of cloth with a floral pattern. Her two low pigtails, which cast a shadow across her ribs, lay across the two mounds on her chest. I was surprised how large they were, given her thin physique.

Finally, there was her face. She was pursing her lips as if she was holding something back. Seeing her glasses reminded me of her middle school self, but lowering my vision to the valley below created a conflict in my head that was difficult to resolve. I could feel my head spinning.

“What...do you think?” She bashfully rubbed her thighs together while looking at me through her glasses.

No matter how hard I tried, I couldn’t reconcile the nostalgia of her bespectacled face with her scantily clad body. Ayai did not have the most attractive body. Even when we’d kissed and hugged, I’d get a little worked up, but I never once thought about touching her chest or butt. But right now... This... This is impossible...

“Uh...” It took me longer than I’d like to admit to get my brain functioning and producing words. “Not bad...I think.”

“Y-You think?! That’s not good enough. I need more of a compliment than that!”

“More than that...?”

Yume turned to where she’d left her bag and rummaged around in it before pulling out her phone and shoving it into my face.

“Method three: find parts of your partner you like and compliment them.”

“Geh.” Even this was part of her calculations?!

If I refused, it’d make this outing effectively pointless. Wait, had she suddenly asked me to go shopping with her just to humiliate me like this?!

“Cat got your tongue? Tell me what you like about me, Mizuto-kun,” Yume said with a faint but triumphant smile.

My eyes once again soaked in the sight of Yume’s body wrapped in a white bikini. Her long, thick, pristinely pale legs protruded from under the skirt. There weren’t any signs of pores on them. I had no doubt that there were a lot of women out there who’d kill for her legs.

Following her legs upwards, past her peach-shaped butt, my eyes were immediately reunited with her tight waist. How could girls have such thin waists? I could’ve sworn that it hadn’t changed even a bit from when we were in middle school. Also, how could she be so small there yet so large in other places? Her chest and butt were comparatively larger than her slender waist. I struggled to understand how she was able to keep her balance all the time.

This brought me to the biggest difference in her body between now and middle school—her breasts. Perhaps swimsuits in general were made to have this kind of effect, or maybe it was just the one that she was wearing, but her breasts looked a lot larger than usual. She had a very visible line of cleavage, over which her pigtails flowed like a river.

When I’d hugged her back in middle school, it’d felt like chest-bumping a brick wall. If I did that now, I doubt I could press my whole body against her. Complimenting her on anything felt like it’d be a form of sexual harassment. I frantically tried to look for something that didn’t mention her bulging chest, her slender waist, or her long legs. I needed something neutral. Was there anything I could talk about that didn’t have to do with her appearance?!

“I...” After racking my brain for an answer, I was finally able to squeeze out the words I’d been looking for. “I like how much you care about your family.”

“Huh?” Yume’s face froze. Her eyes fixed on me and her mouth was left half-open, but there was a slight twitch in her cheek...or at least that’s what I’d expected. Instead, her eyes were darting left and right, her lips were trembling, and she was holding her cheeks with both her hands. “Wh-Why are you complimenting my personality?!”

“What other choice do I have?! Finding something good about you in a swimsuit would be social suicide!”

“Wha—” Yume’s face flushed, and she bumped into the mirror as she backed away from me, all while covering her stomach and chest with her arms. “Y-You pervert! Horndog! You could’ve just complimented the design of the swimsuit! You could’ve said that the color matches me! That’s what you could’ve said!”

“Oh... Good point...” I was filled with so much regret. The saleswoman had picked out the swimsuit, so I’d taken the option of complimenting the choice itself out of the equation.

Yume pulled the curtains around her body and leered at me from behind them. “Now I know exactly how you look at me.”

“You’re the one who told me to look!”

“I-I didn’t tell you to ogle m-my body! Also, that’s not what I meant...”

“Huh?”

“Forget it!” Yume retreated behind the curtain.

I rested my face in my hand, unable to accept what’d just happened. What was she so unhappy about? I fulfilled the request to compliment her. Plus, why was it only me that she...

“Hey,” I said, an idea formulating.

“H-Huh? I-I’m kind of in the middle of changing...”

“We’re looking for a way to get back our tenseness, right? That’s a two-way street. Shouldn’t you find a compliment for me too?”

“What?” The sound of her changing stopped. The only sound for a little bit was from the people in the mall. “I-I guess... Even with all that’s happened, you’ve stuck with me until the end...or something.” Her voice was so low that it should have gotten lost in the sound of the mall, but I definitely heard it.

My hand left my jaw and covered my mouth. Now who’s the one complimenting personalities? I really thought she would’ve said something like “You look good in glasses.”

“Oh, I see. Now I know exactly how you look at me.”

“What’s that supposed to mean?!”

“That you... Well, you see me as a really convenient and easy to handle person.”

“If you’re easy to handle, the entire human race is easy to handle!”

Don’t deny it. Rude. After that, I kept my mouth shut and waited for Yume to finish changing. Ultimately, it took her a lot more time to change back into her clothes than out of them, but at long last, Yume came out of the fitting room.

“I’m...gonna go check out.”

“So you like it?”

“I guess. Yes. I like it.”

The way she emphasized “I” was unnecessary. Why else would she buy clothes if she didn’t like them? I walked with Yume to the register and watched her give the swimsuit to the saleswoman who’d picked it out for her. As she did, the tag on it caught my eye.

9M? I took out my phone to research this befuddling combination of number and letter. I’d never seen it before. Apparently, 9M for a top meant that it was eighty-three centimeters. So a C or D cup. Hm...

“Um, sorry.” Yume leaned over the counter and spoke to the saleswoman in a low voice. “It was a little tight around the chest...”

“Oh, really? I guess you’re a bigger size than you thought.”

Immediately after that, I entered a state of self-effacement, but was eventually snapped out of it by a loud “Thank you very much!” from the saleswoman, her smile still unnaturally wide.

Yume took the bag with her swimsuit in it from the saleswoman. Seeing this, I held out my hand to her.

“Hmph,” I begrudgingly grunted.

“Huh?”

“Give it. I’ll hold it.”

Yume’s eyes fell to the bag that she was holding against her chest.

“Wh-What’s gotten into you? Why are you acting like a gentleman?”

“I see you backing away from me. Stop. I’m just thinking about the balance aspect of all of this. You have a purse to worry about, but I’m empty-handed.”

“Ah...”

This was starting to get annoying, so I snatched the bag from her. It only had a swimsuit in it, so I might as well have been holding air. I immediately moved to walk out of the shop and Yume hurried to catch up. Now we both had something in our hands.

“Hm... Balance.”

“What?”

“No, it’s just that... If you’re thinking about our collective balance, you see the two of us as a pair...”

I stayed silent in order to make sure I chose my words carefully. “Of course I do. We’re walking together. We’re not related by blood, but we’re still technically siblings.”

“Just siblings?”

“Just siblings.”

“Right... Of course.”

The mall was packed with people, probably because it was summer vacation. We had to be careful not to get separated, but it’s not like we needed to hold hands. At least, I didn’t think we needed to. This only reaffirmed how we felt about each other.

“Time to head back?”

“Yeah, let’s go home.”

“Did we get the tenseness back?”

“At the very least, I know that you look at me with lecherous eyes.”

“I told you... You were the one who told me to look.”

Yume quietly giggled. Even without turning to look at her, I knew exactly what kind of expression she had on. She’d put her hand against her mouth and was glancing at me, a soft smile forming on her face.

We were a couple, and then we became siblings. I knew way too much about the different faces she’d make. There was no need for me to look at her face, never mind hold hands. Her voice, her appearance, her very existence—it had become all too natural that she was by my side.

It probably seemed like we were still in the post-honeymoon stage. Whether we were being called a couple by the saleswoman or at the dinner table with our parents, there wasn’t any real difference.

“How about stopping by a bookstore on the way home?”

“Oh yeah, I did wanna pick up a book while we’re out.”

“You have absolutely no intention of stepping one foot outside of your grandmother’s house, do you?”

Just like that, the two of us walked to the bookstore without holding hands. That was perfectly fine.

We got home in the evening. The summer sky looked like it’d been stained red. One by one, we stepped over the shadows of the telephone poles in our path.

“Since we left the house at different times, should we arrive home at different times too?” I asked.

“It shouldn’t matter. We can just say that we ran into each other on the way home.”

“True... We shouldn’t draw too much attention to ourselves.”

Compared to the mall that had been bursting with people, out here, basically nobody was around. From the houses on either side of us, we could hear the sounds of children playing and food being prepared. The only shadows cast by people were mine and Yume’s.

I started to suppress memories that were trying to resurface back to the depths of my brain. I didn’t need them. Not anymore. We were managing. Everything would be solved by time and acclimation. We could live a...well, a not-so-new life without looking back on our dark past—our middle school years.

We’d already spent four months as siblings. The time for doubt had passed. We were siblings who used to date. The past was the past. We needed to focus on the present. Even if we had two titles—exes and siblings—they didn’t encroach on each other. I understood that. I understood, but...

“Ah...” Yume suddenly stopped moving about one step ahead of me.

“This is...”

We’d stopped at where we used to say goodbye before going home. We barely walked this way now that we were in high school. And...

In what could only be described as a folly of youth, I had a so-called girlfriend during eighth and ninth grade.

The sunset staining the way home. The fork in the road leading to our respective houses. Ayai’s slightly red face. A soft sensation left on my lips. These memories flashed in my head one after another. A bespectacled Yume looked up at me from a distance closer than what I remembered from my memories. Right at that moment, a cool wind blew across us, almost sending Yume’s hat flying.

“Ah—” We both reacted.

I quickly stuck out my hand, but so did Yume. As a result, our hands overlapped one another’s. It was the first time that our hands had touched today. The smooth and cold sensation of her hand ran across my fingers. It was as if electricity was running through them.

Everything was in my head. I was dreaming. Hadn’t I already figured that out a mere four months ago? I had a different thought back then. When dad told me about his remarriage, I thought that even at his age, it was impossible to stop dreaming. So if it was impossible at his age, then for high schoolers like us...

Suddenly, I felt the squeeze of Yume’s hand closing around mine. There shouldn’t have been any reason for us to hold hands, but I felt her hand firmly squeezing mine. Like she didn’t want me to let go. Then she took off her hat with her free hand.

This close, I could see her face really well. It was colored red from the sunset. She looked at me as if she was waiting for something.

“Method four... Show your feelings through your actions.”

That one’s easy. I’ve done that over and over and over and over again. If anything... A year ago, everything fell apart because I hadn’t done that.

Yume closed her eyes. I took a step towards her and bent down a little. It was simple. It was really so simple. It would’ve been so simple one year ago.

“Ow!” Yume held her forehead in confusion after I flicked it. “Wh-What was that for?!”

“‘Method two: try surprising them.’”

“Wha—” Yume grew bright red to her ears and began shaking.

I ignored my little stepsister and began walking home.

“Y-You— Right now, you were totally—”

“I did exactly what you said. I showed my feelings through my actions.”

“And what feelings were those exactly?!”

How am I supposed to know? But in that moment, I had been thinking about how if we’d continued...it might have meant reconciliation a year ago, but doing it now just meant we would get dragged back by unresolved feelings.

It’d be as if we were getting rid of everything we’d gone through—the half year of the post-honeymoon phase, the decision to break up, becoming stepsiblings, and me rejecting Isana Higashira. Even if we did that, though, we couldn’t go back in time. I had no regrets.

The reason I rejected Isana Higashira wasn’t that I was still hung up on my ex. I had no reason to think about my past relationship at all—I shouldn’t have had one, at least, but we were family now. Family that was returning to the same home.

“Mizuto-kun, here’s the book you lent me yesterday.”

“Oh. How was it?”

“Good. I thought it’d be really character-driven, but it really went in-depth on the mystery solving.”

“Yeah, I thought it’d be right up your alley, Yume-san.”

“Right. Um...”

“...”

“If you have any other interesting books...”

“Oh. Yeah. Of course.”

We’d successfully gotten back our tenseness. We were acting like stepsiblings who still weren’t accustomed to each other, having finally put some distance between the two of us. Thanks to that, our parents had stopped with the “couple” stuff. But...

“You two are acting kind of distant,” dad pointed out.

“Just like a couple that’s looking for the right timing to propose!” Yuni-san giggled.

While the two of them laughed, Yume began trembling and shot to her feet. “Argh! What are we supposed to do?! You two keep making it so difficult!”

“Aha ha ha! Sorry! It’s just still so weird for me to see you getting along so well with a boy.”

“This’ll get you ready for when we go to my mom’s house,” dad added. “You’re gonna get teased even more. They won’t be able to calm down once they find out that Mizuto has a sister now.”

“I don’t think I want to go anymore...” Yume sulked.

Ultimately, it was just our oversensitive minds at work. Our parents never truly believed anything they said. They were joking around. I’d like to say that they caused us a lot of trouble, but at the very least, we didn’t have anything to worry about anymore. As long as they kept making these jokes, we could stay a family.

“Something wrong?” Yume asked, looking at me.

She wasn’t wearing her nostalgia-inducing glasses today, so I wasn’t forced to remember the old her. Instead, the image of her in her swimsuit was firmly in my mind.

“Nope...” I said, returning my gaze to the book in front of me.

How much was the past and how much was the present? I have no clue. Good grief...