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"...
You mean finally throwing him 
in the bath on my fifth day here?
Du meinst, dass ich ihn nach meinem
5. Tag hier ins Bad gekriegt habe?
¿Hacer que se bañara 
después de cinco días?
¿Hacer que se bañara 
después de cinco días?
alors qu’il prend son bain
après cinq jours ?
Essere riuscito a gettarlo nella vasca
 dopo cinque giorni?
Ao fato de, após cinco dias, eu finalmente
ter conseguido fazer ele tomar banho?