Teppei just transferred into Kaimei Academy, and he's pressured to join the Sket-dan by his classmate, Bossun. Then, one day, Teppei is attacked by a mysterious masked paint chucker, "Paint Mask"!
Wait, that's obviously bogus. 
We're in the school, so...
¡¿Un mafioso?!
¡¿Un mafioso?!
Espera, é claro que isso é mentira.
 Estamos no colégio, então...