There was a boy who insisted on wearing long sleeves even on the hottest summer days.

Kang Seoheon.

I couldn't understand him. He loved sports and sweated every day, complaining about the heat, yet he stubbornly wore long sleeves. I just looked at him like he was crazy.

Then came a certain summer day. The midsummer swelter was swirling through the classroom. Perhaps because there were so few people, the moment I opened the door, the heat seemed to dissipate slightly, and the breeze made me feel much cooler.

Outside, the air was filled with the laughter of children. To me, having retreated to the classroom to avoid the PE lesson on the playground, it felt like a different world.

Sunlight twisted through the curtains and settled on the desks. I was staring blankly at the hot light for a moment when—

Slide—

The sound of the back door opening reached my ears. I looked back and saw a familiar figure. He was the only guy who would wear long sleeves on a day this hot. I was about to look forward again, but he called my name. He was smiling, or rather, the trembling look of momentary embarrassment beneath that smile just made me stop. He waved lightly in greeting. As his long sleeve fluttered slightly, I saw a glimpse of the inside. Bruises, seemingly hidden by force, flashed briefly into view.

It just bothered me. You can get hurt playing basketball. But the fact that there wasn't just one or two of them hit home.

I wondered what had happened to him.