Having come to Canada upon hearing the fake news that his biological mother Haruko is in critical condition, high school student Kaidou Haru meets a young boy named Ren. "You have a new brother. Take care of him." So instructed by his mother, Haru is forced to spend the summer with Ren. Every day is a battle with Ren, who refuses to listen to anybody. However, as Ren grows to like Haru little by little and Haru comes to adore Ren as well, they make a certain "promise"...
his hair was all long, so I shaved 
it while he was in the bath,
tenía el pelo largo así 
que se lo corté en el baño
tenía el pelo largo, así 
que se lo corté en el baño
il avait les cheveux longs.
aveva i capelli lunghissimi,
così glieli ho tagliati mentre si lavava,
tinha um cabelo bem comprido, então aproveitei
enquanto ele tomava banho para cortar com a navalha.