I Promised to Make the Class Honor Student My 'Little Sister'. It Seems She Wants to Be Spoiled a Lot - Volume 1 Chapter 11.2

Me, Touched by the Warmth of a “Family,” Protecting Something Important to My “Sister”

“──So, who knows the three laws called ‘Mendel’s Laws’?”

One day during biology class.

My “twin,” aka Kakogawa Yukari-sensei, surveyed the classroom while pointing at the blackboard.

Though she hasn’t been our class teacher for long, her inherent frankness has made her blend in with the class seamlessly.

“Yes, Takato-kun.”

“…Eh? I didn’t raise my hand, though.”

“I’m calling on you. You were zoning out.”

Seriously?

I stood up while scratching my head, pondering the answer.

Yukari, that sneaky smile on her face… I’ll remember this when we get home.

“Um, the three are… ‘segregation’ and ‘independent assortment’ and… what was it? Something about the dominant gene being inherited from the parents…”

“Okay, thank you. Takato-kun, how about you stand in the hallway? Hm?”

Why the hell? I got two out of three right.

Yukari’s witty black humor elicited laughter from the class.

In that congenial atmosphere, the one who raised her hand was──Ao.

“Then, let’s have Kakogawa-”

“Yes! The three ‘Mendel’s Laws’ are… ‘The Law of Segregation’, ‘The Law of Independent Assortment’, and ‘The Law of Dominance’!”

“Correct!”

Ah, that’s it. “The Law of Dominance”.

Something about the dominant gene between two genes being inherited… that thing.

Recalling what we had learned before, I listened to Yukari’s talk.

“──There’s some debate about the name ‘The Law of Dominance’. For example, if a child resembles their father, does that mean the mother, who doesn’t resemble the child, is inferior!? …It’s a misleading name because of that.”

Then, Yukari wrote some unfamiliar words on the blackboard.

──”Dominant” and “Recessive”.

“Instead of ‘dominant’ and ‘recessive’, you can say it like this. The gene that actually appears is the ‘dominant’ gene. The one that seems not to have been inherited is… the ‘recessive’ gene. But, the character for ‘recessive’ involves ‘concealment’, right? So, what does that mean…?”

“…It means that even if it’s not manifesting, it’s lurking in the genes. Both are properly inherited, right?”

This time, Ao murmured while seated.

Looking at Ao’s face, Yukari──narrowed her eyes and responded.

“Right. Biologically speaking… even if not visible to the eye, the genetic traits of blood-related family are always inherited. That’s not just between parents and children, but also grandparents, relatives──including all of that.”

Yukari gently placed the chalk down and, leaning on the desk, smiling kindly──said to the whole class.

“Well, if you think about it──if we include ancestors up to now, all humans are siblings! Kind of, we’re all connected. So, if you have a place where you feel at ease, you can think of it as ‘family’ and rely on it──that’s perfectly fine. Yukari-sensei guarantees it!”

▲　◇　▼　◆

“Lately, Kakogawa-sensei has been clearly picking on Ryuuki, huh?”

As we were getting ready to leave the classroom, Chitose suddenly said that.

Looking next to me as I closed my bag, sleepy-eyed Chitose was staring intently at me.

“She teases other girls too, right? That’s just her personality, Yukari-sensei.”

“Is that so? But I feel like she interacts with Ryuuki in a particularly joyful way.”

“You think so because you know I’m staying at their house. Let’s just go home.”

Chitose and I left the classroom, heading towards the shoe lockers.

Then, as we were changing from indoor shoes to outdoor shoes.

“…Good for you, Ryuuki. It seems like you’ve become happier at home.”

“…’At home’, huh. I’m just freeloading at someone else’s place, you know?”

“Even so, it’s good to see you happy. Most of our high school life is spent at home and school… and maybe a part-time job, if at all. Compared to adults, our world is probably very narrow. If one of those places is a ‘painful space’──it feels like your whole life is boring, right?”

“I don’t remember saying that much.”

“You said you couldn’t dream about the future.”

Tossing aside the younger me who wanted to be a “manga artist,” my parents only gave me the option to become a “doctor.”

Disillusioned and disheartened by such a family, I eventually gave up on dreaming.

If expressing those feelings as “my whole life being boring”──then maybe that’s true.

“Ah. It’s Takato-kun and Ayumura-kun.”

Just as we left the school gate, a little while later.

Ao, who was waiting at a traffic light, suddenly ran into me and Chitose.

Seeing my face, Ao instantly brightened up like a child.

“It’s rare to see Kakogawa alone.”

“Yeah. I had some shopping to do, so I told everyone to go home first. Look, this. The light bulb in our bathroom burned out, so I had to hurry to buy a new one.”

Ah… right. The light bulb in the bathroom did burn out last night.

It happened when Kizuna was using the bathroom, and she panicked, yelling, “Ao-nee, help! There’s a ghost, it’s coming out!!” And Yukari just laughed.

As usual, Ao is the most dependable person in our house.

In contrast, Yukari is hopelessly unreliable.

“Then, I’ll take my leave here. My train goes in a different direction from Ryuuki’s anyway.”

After patting my shoulder, Chitose walked past me.

He glanced briefly at Ao… and smiled softly.

“I don’t know the details but… Kakogawa-san. Please take care of Ryuuki.”

“Ah… Yes. Leave it to me, Ayumura-kun!”

Then, Chitose went ahead──leaving Ao and me alone.

“Shall we, then? Go home? Ao… Kakogawa?”

“Y-Yes! We’re taking the same train, so shall we go together, Ryu… Takato-kun?”

Awkwardly exchanging those words… we headed towards the station side by side.

──Inside the house, we’re “brother” and “sister”.

Since it’s decided by contract, it’s easy to know how to act.

But in situations like now, where we’re neither purely “siblings” nor just “classmates,” the distance feels awkward, and I’m not quite sure how to behave.

As we walked silently towards the station.

“…Hey”

Ao timidly raised her hand, as if afraid.

“Um… there’s no one here, right? So, can I call you Ryu-kun like I usually do?”

“…Yeah, sure.”

“Yay! Ryu-kun, Ryu-kun, Ryu-kun♪”

As soon as I nodded, Ao happily repeated my name.

Her expression was no longer that of the responsible Ao… but the face of the “younger sister” who clings to me.

“By the way, Ryu-kun, Yukari-nee said we’re going to have a game tournament today.”

“Here it goes… Yukari is going to dominate again, right? Her gamer skills are ridiculously strong.”

“Today she said she’ll give us a handicap. Kizuna got seriously mad the last time.”

And so we──indulged in trivial chatter.

Outside, she’s a high school teacher who chats candidly with students. Inside, she’s a 24-year-old slacker who either plays games or pranks someone──our “twin” Yukari.

Outside, she always looks lethargic but turns into a complete little sister character in front of Ao and Yukari. However, in front of me, she strives to be an adult woman──our “older sister” Kizuna.

Talking about our… “family” like this.

Gradually, both Ao and I softened our expressions.

“Right! For dinner today, I was thinking of making beef stew. You said it’s your favorite, Ryu-kun.”

And then Ao and I started crossing a bridge.

Once we cross this bridge, it’s only a minute or two to the station.

────At such a place.

“Move it!”

“…Kyaa!?”

A bicycle, speeding unusually fast, was coming from the opposite direction.

And since the rider didn’t seem to be avoiding us… Ao and I split to the left and right to dodge.

…However.

When Ao dodged, her bag hit the bridge railing.

And snap──the string connecting her bag broke.

Attached at the end of the string was a somewhat mature brown leather pass case for a high school girl.

But for Ao, it was an unforgettable treasure filled with memories.

“──Ah!?”

Ao let out a small scream.

Then, the string-broken pass case flew into the air.

Eventually, it fell towards the river flowing beneath the bridge…

──This is something I gave to my dad as a Father’s Day gift a long time ago…

──With this, I feel like my mom and dad are always with me…

“──!? Ryu-kun!?”

I thought I heard Ao calling my name.

The world seemed to move in slow motion. An odd sensation of floating.

It felt strange, but I… tracked the path of the swatted pass case with my eyes.

Ah, good… it’s on the bridge.

And so, relieved that I could protect my “sister’s” precious item…

────I fell into the river flowing beneath the bridge.