My Little Sister Suddenly Confessed to Me, but What Am I Supposed to Do by Dating My Little Sister?

Chapter 57: Summer Vacation, the Sea, and Swimsuits!!

“Alright, everyone—please be careful over summer vacation, and make sure to do your homework!”

“Okaaaay!”

What are we, elementary schoolers?!

With that, the final homeroom ended. It felt like “Final exams? What are those?” as the school welcomed summer vacation.

Still, that teacher is as cheerful as ever… was her crying face back then just an illusion?

“Come on, Onii-chan, let’s go home! It’s summer vacation!!”

Called out by my sister, who was at her usual—no, higher than usual—level of tension, we headed out.

The summer sun and heat were exhausting, but I felt relieved knowing I wouldn’t have to commute to school starting tomorrow.

As the two of us walked out of the school gates side by side, the silver-haired beauty Michiru was standing right there.

“Hey, Yuu, Shiori. It’s summer vacation!”

“You look pretty happy about it.”

“What are you talking about? I’m obviously heartbroken.”

“Why? Your words and your attitude don’t match at all.”

“Because… I won’t be able to see you—my friend—very often!”

“You can just invite me out, right?”

“Is it okay for me to invite you?!”

Hmm, I don’t really get it, but if you’re friends, you can invite each other, right?

While I was talking to Michiru, a voice suddenly called out from behind.

“Umm… Umm… Yuu-kun… Shiori-chan…”

This way of speaking—I knew it was Asami without even turning around.

“Hmm? Asami, what’s up?”

She’s next to me every day, but she really has a thin presence, I thought, completely ignoring my own status in class.

“Umm… are youuu… okay right nowww?”

Her slow, relaxed way of speaking was the same as ever.

“Yeah? What is it?”

“Wellll, this is sudden, buttt… are you free for about four daysss… starting the day after tomorrowww?”

Asami suddenly started saying something like that. Four days?

“Well, I don’t have any plans for July yet.”

I looked at my sister, and she nodded.

“You seeee, my family was supposed to go on a trip… but we can’t go anymoreee. Since there’s a cancellation feee, my mom told me to go with my friendsss instead—”

“Eh? But four days means three nights, right? That’ll cost a lot. As expected, that’s a bit much…”

“Wellll, it’s free for two peopleee. My mom won a pair ticket in a sweepstakesss, and we added the rest for a family trippp.”

“But since we can’t gooo, she said it’s a waste to cancel everythinggg—”

“Wait a second, I didn’t ask yet. Where are you going?”

“It’s Ishigaki Islanddd.”

“Ishigaki Island!!”

“Yeahhh. Since it’s a waste to cancelll, she said the money doesn’t matterrr—”

“No, as expected, that’s…”

Just as I thought that, I looked at my sister…

“Onii-chan and Ishigaki Island… white sandy beaches… the blue sea… a summer experience…”

She started muttering and had journeyed to “another world” again. Hey, now…

Still, it felt wrong, and it was a lot of trouble, so I intended to decline.

“Um, it’s a bit sudden, and I’d feel bad,” I said, but…

“Wellll, my mom is worried that I don’t have any friendsss… so if you could gooo, it would actually help me outtt…”

Ugh. As a fellow “loner-type” comrade, when she puts it like that, it’s hard to refuse.

I’m loner-ish, but not a total loner! Look, I’m being invited on a trip—I’m a total normie (riajuu)!!

“Onii-chan, let’s go!!”

Ah, no good. My sister is totally on board…

“Ah… yeah… alright, let’s go…”

Once it reaches this point, my sister won’t budge an inch. Ah, I miss the old days when my sister didn’t act so selfishly…

“I’m sooo happy. Oh, anddd, we have a spot for my little brother too, so there’s room for fourrr. Can Shiori-chan invite a friend or somethinggg?”

She didn’t ask about my friends? Ah, well, a guy would be bad… so that’s what you mean, Asamiii…

“Is your brother not going?”

“Yeahhh. He caught the measles yesterdayyy, so he’s in bed nowww.”

“Measles…” So that’s the cause… the little brother.

“One more person, huh…”

Well, if it’s my sister’s friend, they’d definitely go, but it feels like there’d be a rush for it—like a war over a premium ticket.

If that happened, it would be bad. Just as I thought that, I felt a gaze…

Michiru was staring intently at us.

Staring.

Staring…

Ah, she was staring with a face that looked like she was about to cry…

“Um… Michiru-san, do you want to go?”

“Eh?! Is it okay?! For me to go along? No, I’d feel bad—it’s our first time meeting, yet I’m being invited to such a wonderful place.”

“Let’s see, it’s the day after tomorrow, right? Ah! I just happen to be free! Yeah, it’s fine!”

“Ah… I see… Asami, Michiru is an old friend of mine… from way back. Is it okay?”

“Yeahhh, it’s fineee. Michiru-san, will you be my friend tooo?”

“Of course! Asami-chan, from this moment on, we are best friends!!”

“You’re so quick to jump on board, Michiru…”

“Hmm? Did you say something, Yuu?”

“No, nothing—”

“Honestly, you’re just jealous because Asami-chan has more friends now.”

“I am not jealous!!”

Wait, why is water coming from my eyes…? I’m just happy that Asami has more friends now.

That’s right. That must be it… ughhh.

“Thennn, is it okay to meet at the station at 9:00 AM the day after tomorrowww?”

“Okay!”

“Sure!”

The two of them replied happily.

Right at the start of summer vacation, a trip to Ishigaki Island was suddenly decided… seriously? Me and three girls…

Chapter 58: Summer Vacation, the Sea, and Swimsuits!!

After parting with Asami and the others, on the way back home, my sister’s excitement had reached its peak.

“Wow! Wow! Onii-chan, Ishigaki Island! We’re skipping Okinawa and going straight to Ishigaki Island!!”

“Before that, we have to convince Mom.”

I had told them I’d give a proper answer after getting my parents’ permission.

“Eh? It’ll be fine. If I said I was going with three girls, she might say no, but since you’re coming along, Onii-chan… Mom actually trusts you, despite how she looks.”

“Well, both Dad and Mom are pretty easygoing about everything.”

My mother is a nurse, but I often worry if someone so laid-back is actually okay on the job.

“I won’t deny that.”

The two of us burst out laughing. They’ve always been so carefree that we siblings grew up with a strong sense of responsibility, feeling like we had to be the sensible ones.

“Ah, right. I have to prepare for the trip, so come shopping with me tomorrow!”

“Shopping? What are we buying?”

“Ehhhh, isn’t it obvious? A swimsuit!!”

“I have to go too…?”

“Ishigaki~ the sea~ with Onii-chan~♪”

My sister hummed a tune as she walked beside me. She’s even good at humming; what is with this all-purpose sister?

“You’re in a surprisingly good mood even though Asami and Michiru are coming, Shiori.”

She’s gone past being a jealous type into a “Jealous-Yandere” (Jeya-yan) sister, yet even though we’re going with Asami and Michiru, she’s in high spirits. I felt a sense of doubt as to why.

“Ehhhh, well, it’s Ishigaki! And besides—ah! You haven’t noticed, Onii-chan!”

“Eh? Noticed what?”

“I see~ so you haven’t noticed. I think you’d understand if you had listened closely to what Asami-chan said.”

“Ehhh? What? I don’t get it.”

“Ehehehehe. Well, I’m not entirely sure myself, but… it’s a secret! It’ll be a treat for when we get there. Ehehehe.”

What could it be? She has that ridiculous ability to get top grades just by listening to school lectures, so maybe she caught something. For an average person, just deciphering Asami’s slow speech is a chore.

Ahh, I’m already anxious, and now I’m incredibly curious. What is it…?

“Ehehehe, uhaha, Ishigaki Island~ with Onii-chan~”

My sister and I returned home in completely opposite mental states.

######################

“See? It was totally fine, wasn’t it?”

In the end, Mom just said, “Heh, is that your friend? Aren’t you just following Shiori’s friend?”

Mom… I guess I’ll bring you a habu snake as a souvenir. A live one. (They don’t sell those.)

“It was fine, but why do I feel like I want to go even less now…?”

The day before departure, my sister and I were at the swimsuit section of a shopping center. Why haven’t we reached Ishigaki yet? There’s a lot of research to be done, for both me and the author…

“Now, Onii-chan, pick a swimsuit for me. One that you like!”

“A swimsuit, huh…”

“I’ll wear whatever swimsuit you like. Separates, bikinis, tankinis…”

“What’s a tankini?”

“String bikinis, T-backs, V-fronts…”

“What’s a V-front?”

“School swimsuits, old-style ones, or even the old-old-style ones.”

“What on earth is ‘old-old-style’?”

“Eh! N-no way, Onii-chan, you want me to wear that…?”

My sister pointed at a swimsuit with a trembling hand.

“A toddler’s swimsuit… Why would I pick that?!”

“Eh? Because in that manga magazine you have hidden behind the books on your bookshelf…”

“Why do you know the location?! I changed it! I put so much thought into a spot that would never be found, and yet…!!!”

“I know everything about you, Onii-chan.”

“Shiori! Since when have you been sneaking into my room?! I’m putting a lock on it! And unlike the author, I don’t have those tastes! That was just drawn in the back of a magazine I actually wanted to read!” (Hey!!!)

“Then, which one is good, Onii-chan?”

“Whatever’s fine. I want to go home… where should I hide things next…”

“So, it’s between a bikini, a one-piece, or a school swimsuit, right?”

“Why are you so obsessed with school swimsuits…? Shiori-san, honestly, it’s painful being here. People are staring at me like I’m in the lingerie section…”

“Ehhhh, but I wanted you to choose… Ah, but I guess it’ll be cuter if I show you for the first time over there.”

“Anything you wear will look good. I’ll be at the bookstore, so take your time. Anything except a school swimsuit…”

“Then, sorry, Onii-chan. I’ll finish up as fast as I can.”

I told her to take her time and headed to the bookstore.

“Geh!!”

“My, what a coincidence. And what’s with the ‘geh’!”

“It has been a while since the volunteer incident, President…”

Inside the bookstore, there was the Student Council President.

“Indeed. I mean, what is with that sister of yours?”

“Ah, who knows…”

“She’s beyond inconsiderate. And you, you’re always with your sister.”

“Ah, well, I suppose I am.”

Because lately, she won’t leave my side. Not at home, not at school.

“This is perfect. I have something to talk to you about. Come with me for a bit.”

“Ah, no, my sister is—”

“Good grief… then give me your phone.”

“Eh? That’s…”

“Just. Give. It. Over. Now!”

She grabbed my collar and yanked me toward her. Hey, I can’t breathe! And people are watching…!

She snatched my phone and opened LINE.

“Hmph. You don’t have anyone registered.”

I do! Like my sister, Asami, and Mom… ugh.

“None of your business! Just give it back.”

“Here. I’ve registered myself. I’ll call you next time I have time. If you ‘Read and Ignore’ me, I won’t let you off easy.”

Then I’ll just ‘Unread and Ignore’ you.

“Honestly, what do you want? Come to think of it, you’re not wearing the blonde wig today. Your outfit is pretty plain, too.”

She had her hair in her school style—that reddish-tinted color—and was wearing a normal shirt and denim. Her figure is amazing, though.

“Stop calling it a wig. I’m probably… not going to do the blonde thing anymore…”

For a split second, the President looked incredibly lonely. I could sense that something had happened.

“Hmph. Well, see you later. If you ignore me, I’ll ‘do’ you.”

She left without specifying what she meant by ‘do’.

“She really tracked me down. To see through my plan to ignore her… as expected… though I’ve never actually done it…”

Between Ishigaki Island and the President, why is my summer vacation already looking so bleak right at the start?

Chapter 59: Summer Vacation, the Sea, and Swimsuits!!

The day of our departure for Ishigaki Island arrived, and I left the house with my sister.

“With Onii-chan, to Ishigaki Island~~♪”

Her tension had been at a peak since the day before yesterday, while mine was at rock bottom. The difference in altitude was so high my ears were…

I wasn’t even in the mood to finish that old comedy gag as we walked toward the station.

Today’s coordination for my sister: a linen light pink shirt layered over a black sleeveless tank top, tied at the waist. Her bottom was a white culotte skirt, paired with sandal heels and sunglasses tucked into her neckline. As always, she was fashionable and cute.

Me? Do you really want to know? A T-shirt and beige half-pants…

When we reached the station, Asami was already waiting. She wore a white-based floral long one-piece dress with a slightly open neckline. Since I rarely see Asami in private clothes, it felt fresh.

Since we were in one of the hottest prefectures in the country, today felt like we were being boiled alive. Asami stood in the shade, but sweat trickled down her neck and into the lush valley of her chest, and I involuntarily found my eyes drawn to it…

“Gyah!”

My sister stepped on my foot with all her might as she walked past me. I mean, it can’t be helped—I’m going to look!

“Michiru-chan, good morning!”

Without even acknowledging that she’d crushed my foot, my sister greeted Michiru. Michiru came rolling her suitcase out from the station…

“Michiru, that outfit…”

I spoke to her, feeling slightly taken aback.

“Eh? Does it not suit me?”

“No, well, it suits you, but…”

Michiru appeared in a blue and white bordered tube top (showing her midriff) and hot pants, wearing large sunglasses.

“Um, when I told them at the shop I was going to Ishigaki Island, they recommended this… is it weird?”

Since she’s a silver-haired beauty, it fits her, but it’s certainly flashy… For now, her chest is almost unchanged from when we met in elementary school… Welcome back, Michiru…

“I feel like you just imagined something very rude.”

Ignoring Michiru’s comment:

“Alright, everyone’s here. Shall we head to Ishigaki?”

“Oooooh!” we shouted in unison as we headed toward Haneda Airport.

After a little over an hour, we reached Haneda. Since we had time, we decided to get tea, but first, we checked in and dropped off our luggage.

While struggling with the automated baggage drop, we still had time to spare, so we sat in a café. Asami began talking about today’s plans.

“Check-in at the hotel is at 3:00 PM, so we can go in as soon as we arrive… but since the timing is what it is, maybe it’s better to do a little sightseeing firsttt… do you think we have timeee?”

“That sounds good—I want to see something. Is there a specific spot?”

Looking at the guidebook Asami brought, the three girls decided where to go.

“From tomorrowww, the hotel has a beach, so we can swim thereee… and how about going on a Yaeyama sightseeing tourrr?”

“Let’s decide that at the hotel tonight. This was originally Asami’s trip, so we should prioritize where you want to go.”

After all, this was originally Asami’s vacation; we were just lucky additions.

“Eh, it’s okayyy. We can go where everyone wants to gooo.”

“Well, let’s think about it on the plane too—”

My high-tension sister wrapped up the conversation, and boarding time arrived.

…Actually, it arrived too soon.

Even though it was summer vacation, we were departing on a weekday, so the plane was fairly empty. Since it wasn’t a massive aircraft, the four of us couldn’t sit in a single row, so we took two window seats, one row behind the other.

My sister and I sat together, with Asami and Michiru in front of us.

“Onii-chan, it’s been a while since we rode a plane, hasn’t it?”

We’d only ridden one once before on a family trip…

“Hmm? Onii-chan, what’s wrong?”

I confessed to my sister in a low voice.

“Actually… I’m not good with planes.”

“Ehh! Really?!”

“Shhhh!”

The two in front looked back through the gap in the seats. My sister and I waved our hands to play it off.

“Ehh, I didn’t know. That’s why you haven’t been very energetic. Why?”

“Well, remember when we rode one in elementary school? The acceleration during takeoff surprised me. It wasn’t too bad then, but later I read a book about the ‘Critical 11 Minutes’…”

“The Critical 11 Minutes?”

The engine noise began to resonate, and my tension rose steadily.

“Y-yeah. There are these ‘Critical 11 Minutes’ in flight. They say the 11 minutes during takeoff and landing are the most dangerous. Especially takeoff…”

“Isn’t it landing?”

“Landing is dangerous too, but apparently many pilots say takeoff is scarier. They push the engines to the limit, so they can break. But even if they break, you’ve already gained too much speed to stop, so you have to fly. If you only have one engine left, you might not have enough power and crash… I read that and got scared.”

“Heeeh, I see… That is scary, Onii-chan.”

“You seem fine, Shiori…”

“Yeah. Right now, I’m totally fine.”

“Right now?”

“Yeah. Because even if we fall and die, I’ll be with you, right? If it were just you or just me, I’d be scared to hear that, but…”

Saying that, my sister took my hand.

“I told you before, didn’t I? Even if it’s hell, as long as I’m with you, I’m happy.”

Eventually, the plane accelerated. When I squeezed her hand, she squeezed back.

Why does this perfect sister love me—a pathetic brother with no redeeming qualities—this much? I truly wanted to know what it was, or what had triggered it.