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"...
Huh? What progress?
Hä? Weiterentwicklung?
Wie meinst du das?
¿A eso le dices progreso?
¿A eso le llamas progreso?
Eh? Che progressi?
Quê? A que progresso você se refere?