My Stepsister is My Ex-Girlfriend - Volume 3 - Chapter 1

A Day in the Life of the Ex-Couple

An Invader in the Midst of a Storm

The storm raged outside.

“All the trains have stopped, so I don’t think we can come back tonight. I did manage to meet up with Yuni-san, so—”

“Happy house-sitting with Yume, Mizuto-kun!”

I replied with an “okay” before hanging up the phone. I peeked outside at our yard and was met with the sight of rain pelting our windows.

We were more than halfway into June. As we drew ever closer to summer, we also drew closer to the typhoon season. Today’s storm was at least considerate enough to have started its torrential pouring after school and work hours. One moment everything had seemed normal, but in the blink of an eye, everybody was confined indoors.

“So?” my little stepsister asked. “Can they get back?”

“Nope,” I said without turning to face her. “They’re staying the night in a hotel, so they won’t be back till tomorrow.”

The sound of the rain pounding our home reverberated across the living room in which we were the only occupants. In fact, we were the only ones in the whole house, meaning that we had to somehow ride out the night. Alone.

“So, uhhh... How ’bout we start on dinner?” I suggested. “What do we have in the fridge?”

“Hm, I think we have some frozen foods.” She paused. “Oh, I should make rice.”

What? Are you surprised we’re not freaking out after realizing that it’s just the two of us for an entire night? Well, we’ve been living together for about three months, and during that time, there’ve been countless situations in which we’ve been left home alone. True, this may have been the first time that we were alone overnight, but it would be nothing more than an extension of the times we’ve been left alone before.

Humans learn and grow from their experiences. This trifling situation was nothing to us...or so I thought.

After we finished dinner, took our baths, and went to our separate rooms, I heard a high-pitched shriek from Yume’s room.

Hm, is someone dying in there? I furrowed my brow and left my room to figure out what she was freaking out about in the middle of the night. The second I opened my door, a long-haired specter immediately jumped onto me.

I yelped, thinking I was under attack by Sadako, but no, it was just my little stepsister. As she pressed her face into my shoulder, I did my best to try and ignore the floral smell from her long black hair, which was tied into two low pigtails.

“Wh-What happened?” I asked her in a calm, cool, and collected voice. Yume pointed towards her door, her entire body trembling.

“I-It... It’s...”

“Does ‘it’ have a name?”

How was I supposed to know what she was talking about if she wouldn’t say what it was? For all I knew, it could have been Voldemort, but a quick glance into her room was enough to tell me that wasn’t the case.

My eyes landed on her carpet and that’s where I saw it-which-must-not-be-named. A small effigy of darkness that could move at unimaginable speeds.

“D-Do something! Bug spray! Where is it?!”

My mind raced as I went through the various options, trying to find the best one as quickly as possible. As soon as the answer dawned on me, I slowly approached the open door, clasped my fingers around the handle, and...slammed it shut, sealing the danger in there.

“Seal complete,” I said, slowly putting distance between me and the door.

“You sealed it in my room!” She shot me a glare as she jolted back. “Don’t tell me you’re scared of bugs.”

“I suppose that’s one way to put it.”

“That’s the only way to put it! Aren’t you embarrassed?! I could’ve loved you for a hundred years, and this would’ve been enough to kill our relationship.”

“Well, you were only into me for a year at most—a far cry from a hundred years—and it’s already dead.”

We retreated to my room, Yume firmly clinging to my arm every step of the way, in order to strategize our next steps.

“Whatever! Just get the bug spray! I don’t know where it is!”

“Yeah, and if I do that, you’ll make me kill it. God, why is it that you only play the damsel in distress at times like these? Pisses me off!”

“It’s better than being a wimpy guy!”

Either way though, I had no choice but to go get the bug spray from downstairs. As expected, when I came back up, Yume hid behind me and mumbled, “All you.” Dammit, I usually leave this stuff to dad. Why does he have to be gone today of all days?!

I steeled myself, gripped the can, and opened the door to Yume’s room. As I peered inside, I focused on the area of the carpet where I’d seen it last, and then ran my eyes across the floor. Even though Yume had a lot of books, her room was tidy. So, unlike me, she didn’t have lots of clutter across the floor. Instead, her collection of books (in the triple digits) were neatly packed into bookshelves or boxes. That should have created a situation where there were no blind spots, but...

“I don’t know where it went.” It appeared that it’d concealed its disgusting self from us. “Okay, we have no choice but to try a saturation attack. We’ll use a bug bomb and give it no place to escape.”

“Wait, then where am I supposed to sleep?”

“How about in our parents’ room?”

“Huh?! You’re saying I should sleep in a married couple’s bed?!”

Honestly, that hadn’t crossed my mind. I’d just figured that she wouldn’t mind sleeping in her mom’s bed.

“Fine, then what about the couch?”

“No.”

“Okay... Then I’ll sleep on the couch, and you can sleep in my—”

“No,” she flatly refused while gripping the sleeve of my pajamas. “I don’t know what I’ll do if that thing pops up again.”

I wondered what the heck she expected me to do when we’d both be frozen in fear. There’d be nothing to do. Is she stupid?

After placing the bug bomb in her room, I finished off the seal by spraying the space underneath the door. Fortunately, she didn’t have a computer in her room, or else I would’ve had to go in and move it.

“Now it has nowhere to run. No way it’ll survive this.”

“Don’t jinx it—now it’s definitely gonna live.”

“Dang.”

After our exchange, we headed back to my room. As Yume carefully waded through the sea of books strewn across my floor, I could see that she was making a difficult face.

“Why did it show up in my room when your room is so much dirtier?”

“Maybe it’s ’cause I ventilate my room in the winter. There’s no way for their eggs to survive when my room gets that cold.” I paused, remembering something. “Oh yeah, I guess your room used to be empty, so we never aired it out or anything.”

“Argh, god!” she growled before angrily plopping on my bed.

Her pigtails, which were held together by white scrunchies, rested on her pajama-clad chest. Regrettably, this was a very nostalgic sight for me, so maybe that’s why an unexpected question escaped my lips.

“Are you serious right now?”

“What are you so worried about?” she asked, leering at me. “Are you that worried that you can’t keep your hands to yourself?” Yume leaned back, hands on my bed, like she wasn’t worried about anything at all. The only protection she had were the thin pajamas she was wearing.

She’d only ever dressed this way in front of her family and her ex-boyfriend—aka me. She must’ve been pretty courageous to boldly flaunt her chest like this.

Does she wear a bra to bed? No, scratch that. I needed to seal intrusive thoughts like that away just like the bug. I had to be courageous and rational in turn.

“I’m not worried about anything.”

“Hmph. Of course you aren’t. You are the same guy who didn’t make a single move on your girlfriend in middle school.”

“Cram it.”

I put one knee on the edge of the bed and flipped the blanket over.

“There you go.”

“I’m sleeping...next to the wall?”

“Yeah. Problem?”

“No... That’s fine.”

It wasn’t until Yume restlessly crawled onto her side of the bed that I realized all too late that she effectively had no way to escape. But it was unlikely that she’d need to escape so there shouldn’t be a problem.

After she settled in and faced the wall, I entered my side of the bed and used the remote to turn off the lights. Suddenly, darkness filled my eyes, the sound of breathing reverberated in my ears, and I could feel a warmth on my back as I lay on my side.

As much as I wanted to naturally distance myself, I almost fell off the bed trying to do so. I backed away from the edge, and my derriere was met with something soft, prompting me to reflexively move away again.

My range of movement was very limited; moving my legs even a little had me brushing up against her smooth calf. Every time I encountered it, I would freak out and pull away, end up touching it again, pull away, over and over again. In the end, I gave up and let it happen—but just with my heel.

I knew that if I left the situation unattended, she’d shift positions, and her foot would end up on top of mine. Of course, that was unacceptable, so I shifted my position, and in retaliation, she fought back by sandwiching my foot in between both of hers.

In an attempt to break free, I used my big toe to poke at the back of her foot, but she fought back by doing the same thing. After enough poking, she wedged her big toe between two of mine. Ouch. So I squeezed her toe with all my might. That’s when our hands came into play.

At first, I wasn’t sure what to do when she shoved her hand against my back, but I ended up grabbing it and rolled over. I pushed my fingers in between hers and clenched them. We ended in a stalemate with both of our fingers sandwiched in between one another’s.

Suddenly, the raging storm outside didn’t sound loud at all. It was physically impossible for either dad or Yuni-san to come home today. No matter what we did here, there was no way for our parents to know.

Wait, “no matter what we did”? What was I thinking? This must be the fatigue talking. That had to be it. In the first place, the piece of furniture known as “the bed” had no other use besides sleeping. Only sleeping. Nothing else.

So, in this house that was currently only occupied by the two of us for the entire night with no chance of anyone else coming in, there was absolutely—and I mean absolutely—nothing for me to be considering.

As I was thinking that, I felt two arms strongly embrace me from behind, making me jump a little. As I looked down, I confirmed that there were certainly two arms protruding from under my armpits and wrapped around my chest. On my back, I could feel a soft sensation separated from me by a thin cloth, and accompanying all of this was a hot breath on my neck.

There’s no way this is actually happening. You were the one who was against this. You provoked me, and now you’re doing this?! My ears were filled with the pounding of a heart. At this point, it was hard to tell if it was mine or hers.

Oh no. Not good. I need to hold back. I tried to press my hand against my heart to calm it, but her hand was already there. I had no choice; I turned to face her.

“H-Hey...” Yume started, her voice shaking. “D-Did you hear something?”

“Huh?” I focused on my hearing, and that’s when I heard something.

Suddenly, it was like a bucket of cold water had been dumped on me. Now my heart was racing for a completely different reason. Was the seal too weak?!

“G-Get the lights!” she shouted.

“I know!”

I flipped the lights back on with the remote by my pillow and scanned the room. Then, I saw a shadow of darkness between a pile of books on the floor.

The two of us screamed in unison. Dammit! How dare you?!

“Bug spray! Use the bug spray!” Yume cried as she clung to my back.

Dammit, I can’t move like this. Does the “fight” option not exist for you in these situations? Fortunately, I’d had the foresight to bring the bug spray with me, just in case. But I had so much crap in my room that if I lost track of the creature, there was little hope that I’d be able to find it again.

“I just gotta go for it!”

I stepped off my bed, spray can in hand, and slowly approached it, doing my best not to scare it off. Unfortunately, it somehow sensed the danger it was in, and just as I was about to pull the trigger, it ran off.

“Oh no you don’t!”

My reflexes at that moment should go in the book of world records. I immediately shot the spray straight into its path with an accuracy that pro gamers would applaud. The spray made contact with the shadow, immediately stopping its movement. Even after it had stopped moving, I continued to spray and spray.

“Ew, it’s still alive.” I shuddered.

God, it’s, like, super gross. Ew, I can’t even right now. Though my disgust for this organism was evoking a high school girl’s thought pattern, I continued to spray it, making sure to kill it at least a hundred times over. I wondered if this was how a big bad feels, killing the protag over and over again. I kinda wanted to throw out some insults even.

After a few dozen seconds had passed, Yume called out from behind me. “Is it dead?”

“Probably...”

I had a feeling that if I gave her a definite answer, it’d somehow come back to life. What was this organism? Was it the kind of boss that had different phases?

Sure, it was dead, but I still had to dispose of it. I covered its body with a tissue—kind of like what people do for corpses—scooped it up with a dustpan, and then put it inside several plastic bags. This time, it was perfect.

Yume let out a deep sigh of relief as she saw me tie up the outer plastic bag.

“Hey, you just gonna sit there?”

“Wh-What’s wrong with that?” She huffed. “This is probably the only kind of situation I’ll ever rely on you in.”

“What am I, an exterminator?” I let out a heavy sigh.

“Thanks...” Yume said guiltily.

“Oh, now you thank me?”

“Wh-What does it matter when I thank you?! Be grateful!”

I scoffed in response.

“Now that it’s dead, I have no reason to be here anymore. I’ll just air out my room and—”

“In the middle of a typhoon?”

She didn’t respond.

The sound of rain pelting the window once again filled the room. Though she may have been able to get rid of the fumes from the bug bomb if she opened her window, she’d also have a good amount of water fill her room—a room packed with books.

“Plus, you know what they say: if you see one, there’s bound to be thirty more behind it. It’s better to wait for the bug bomb to do its job.”

“Well, it is what it is, I guess...” Yume averted her gaze from mine. “Just for today.”

“Where’s my ‘thank you’?”

“Shut up! You should be thanking me!”

When morning came, the sound of rain and wind had both disappeared, and in its place was the soft sound of breathing. In my half-asleep state, I turned to face the source of the sound out of reflex, and my eyes were filled with the sight of a cute girl with long eyelashes, fast asleep.

When was the last time I saw your face this closely? You’ve always had such nice facial features, but no matter how many times I told you that, you’d never believe it yourself. And now you try to play the role of a perfect, beautiful, and intelligent superhuman. For god’s sake...

I moved her bangs to the side so I could see her face better. It’s okay if you at least show me what you really look like, right, Ayai? Her warm breath brushed against my lips.

Then I heard a sound and a current of electricity ran through my body, making me jump. Oh no, was that— More importantly, what the heck was I just trying to do?! Just as my slowly booting-up head started to overheat, Yume, who was supposed to be asleep, jumped up and grabbed me.

“Ah!” she yelped.

“Huh?”

I heard the sound again, so I turned around to the source and saw that a few of my school papers had fallen to the ground. So that’s what it was. Then the real problem I needed to focus on was the girl who currently had her head burrowed into my chest.

“H-Have you...”

She said nothing.

“Have you been awake this entire time?”

Still nothing.

Had she caught on? Did she know what I had tried to do while I was half-asleep? Yume continued to keep her head against me, hiding her face.

“No comment. I have nothing to say to a guy who would try to kiss a sleeping girl.”

“If you knew, then—”

“What time is it?!” Yume suddenly shouted, let go of me, and jumped off the bed. “We’re gonna be late if we keep dawdling! The typhoon’s obviously gone by now.” She dashed out of the room, not letting me get a single word in.

I stared at the now closed door and muttered, “If you knew, then...” You could have at least tried to move away.

Those last words never left my mouth and instead slowly passed, just like the storm.