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"...
I'm not going back yet. 
Summer break is only halfway over.
Ich bleibe hier.
Aún no. Falta la mitad de las vacaciones.
Aún no. Falta la mitad de las vacaciones.
Je reste ici.
Non ci tornerò così presto.
Le vacanze estive sono solo a metà.
Não vou, não. Só se passaram 
 metade das minhas férias,