Fallen from the Top Group Due to Cheating and False Accusations. The Only One Who Stood by Me Was My Little Sister’s Best Friend, Who Had Always Adored Me.

Chapter 1: An Ominous Premonition.

“I’m home~! And I’m heading out again~!”

After stepping into the entryway and dropping my bag in my room on the second floor, I quickly grabbed my smartphone and wallet, then hurried down the stairs.

It was April 22nd, 7 p.m. Normally, after returning exhausted from club practice, I would head straight to the bath to recover. But today, as Rindou Arata, I had to break that routine—no matter what. There was someone I absolutely needed to see, and I was running a little late because of it.

The reason was something I could only call youthful impulsiveness. I was on my way to meet my childhood friend and girlfriend, Matsunami Karen, whom I had started dating last spring in our first year of high school.

“I wonder if she’ll be surprised if I suddenly show up with cake.”

Yes—today was our one-year anniversary.

From elementary school onward, Karen had been the soccer club’s manager, always supporting me and my best friend Kayama Hayato as we aimed for the national tournament. Last year on this exact day, I had finally worked up the courage to confess, and we began dating.

I was well aware of how blessed my youth had been—smooth sailing in every sense.

My grades were average at best, and soccer was pretty much my only real talent. I was an ordinary guy. Yet Karen was the undisputed beauty of our local elementary and middle schools, the unreachable flower that every boy dreamed of.

When she chose someone like me, I honestly couldn’t believe it at first. More than anything, though, it made me swear to become a man worthy of her.

Our soccer team had fallen short in the Kanto finals last year, just barely missing the Inter-High. I promised her I would take her to the national stage next year, and lately I had even started staying behind for an extra hour of solo training after practice.

That was why I ended up coming home so late today. Still, Karen’s apartment was only about fifteen minutes from my house, so I figured it wouldn’t be too much of a bother.

I picked up the whole cake from the station-area shop that she loved and was about to head out when a sharp voice called out behind me.

“Huh? Onii-chan?”

I turned around. Two girls in the uniforms of different high schools stood on the stairs, staring at me with wide eyes.

The one in front, with long, straight black hair, was my little sister, Rindou Sayu. Behind her stood a girl with innocent features and long, deep-purple hair tied in twin side-tails—Tozawa Yuuka, Sayu’s best friend since elementary school.

I wasn’t surprised to see Yuuka at our house; we had known each other for a long time. They were probably working on homework together. Even though the two of them went to different high schools now, they were still as close as ever. I found myself quietly impressed.

“What’s up, Sayu?”

“What do you mean, ‘what’s up’…?! That’s how you talk to your little sister?!”

“Keep it down. You’ll bother the neighbors. And—Yuuka-chan, good evening! It’s been a while, hasn’t it?”

I pressed a finger to my lips, then shifted my gaze to Yuuka. The moment I did, she dashed past Sayu and threw herself into my chest.

“It’s been so long! Rindou-senpai!”

Her sudden embrace nearly knocked me off balance, but I managed to steady myself. As I did, the faint, sweet scent of osmanthus shampoo drifted up from her hair.

“Now that I think about it, no wonder it felt familiar. Yuuka-chan, you’re wearing the same blazer as me, right? When Sayu told me, I was really surprised.”

Sayu, who had somehow gotten into the prefecture’s most difficult high school despite her height, wore a brown-based blazer. Yuuka, on the other hand, wore the familiar navy one—just like mine. Strangely enough, even though her grades were better than Sayu’s, she had deliberately chosen to enroll at the same private school as me, Hikarigaoka High School, and had done so as the top student.

“It’s kind of frustrating… Yuuka-chan is smarter than her, yet only my little sister gets to wear a different uniform.”

“Hey, Onii-chan! Are you picking a fight with me?!”

Sayu puffed out her cheeks in her usual easy-to-tease manner. Yuuka, meanwhile, smiled happily before blushing shyly and pressing herself even closer.

“It’s fine with me. I decided a long time ago that I would definitely go to the same school as Senpai.”

“Yuuka-chan… I do have a girlfriend right now, you know.”

“I know. I hear about it from Sayu all the time. But that doesn’t matter. We’re Senpai and me, so it’s okay, right?”

“No, I think it does matter…”

It was true that Yuuka had been coming over to play since we were in the lower grades of elementary school. I had spent nearly every day with her and had always treated her like a real little sister—more obedient and easier to get along with than the cheeky Sayu. But at some point, I had started keeping my distance.

The reason was simple: my mental age had caught up.

Even after entering middle school, Yuuka never stopped pressing her body against mine. If anything, the distance between us grew smaller by the day, and her affection for me had become unmistakably intense.

In our second year of middle school, I could no longer ignore the feelings she directed at me. One day, she suddenly barged into my upperclassmen classroom and cornered me with nowhere to run. In the equipment storage shed, she clung to me and said, “Please go out with me. Seriously.”

It was the first confession I had ever received in my life.

I didn’t want to make her cry, and part of me was genuinely happy. But I couldn’t bring myself to lay a hand on my little sister’s friend, a junior. Above all, my heart was already completely occupied by Karen. So I told her the truth.

That day, she left in tears. The next day, however, she came back with her usual bright smile and said, “Please don’t worry about it.” Before long, we had returned to our normal relationship as if nothing had happened.

Even after that, Yuuka would occasionally approach me with invitations and temptations. Each time, I wrestled with myself, but the time we spent together was undeniably fun.

Of course, I never once gave her the answer she wanted.

I could feel how serious her feelings for me were, but I believed they were nothing more than dependence born from our shared childhood. She was popular among her classmates, and I feared that if things continued this way, her own youth would be ruined.

Soon after, I officially started dating Karen, and gradually we stopped seeing each other at all.

That was why running into her now—after a year and a half—felt incredibly awkward to me. Yuuka, however, showed no such hesitation and clung tightly to my arm.

“Ah, Senpai, have you started working out? Your arms feel a little thicker than before.”

“Well, I’ve been going to the gym for extra training outside of club practice. Sorry, Yuuka-chan, but I’m really in a hurry right now… I’d appreciate it if you could let go.”

“Come on… That’s right, Yuuka. If you want a boyfriend, you should stop chasing after this taken idiot and just catch a boy your own age already. Any guy would fall for you the moment you showed interest.”

Sayu sighed in her usual exasperated way at our routine exchange. I shot her a pleading glance. Yes, exactly like that.

“It’s not that simple, Sayu.”

Yuuka, showing no sign of remorse, poked and prodded my upper arm while murmuring stubbornly.

“I know you have a beautiful second-year girlfriend, Senpai. And I know you don’t have even a millimeter of interest in me.”

“Haa…? Then why don’t you just give up already?”

Still clinging to my arm, Yuuka lifted her chest slightly and looked up at me with those innocent eyes.

“I’m pretty stubborn, you know. Even if I realize I’m the losing heroine… I’m the type who just keeps devoting herself.”

“I already know that all too painfully well… But sorry, time’s really running out. I’ll head out now.”

Unable to bear it any longer, I smoothly slipped out of her hold and opened the front door.

“Geez… Don’t run away, Senpai. You big dummy.”

With her dissatisfied voice at my back, I dashed out of the house.

Outside, rain had begun to fall in scattered drops. On impulse as I left, I grabbed a plastic umbrella.