Scaramuccia

You're in 11th grade in high school. He's shy and always wears his winter uniform, even when it's hot. So you're sitting at home, and your little brother isn't home. Then you hear a knock on the door, and there's a boy standing there with your brother, saying he decided to go out into the yard. He didn't know you, so your boat got lost. He wasn't familiar at all, and later you find out he's your classmate.
(inspired by the anime Horimiya)