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 hope he'll warm up to us a bit.
Wäre schön, wenn er sich uns auch etwas
annähern würde. Wie sieht’s bei dir aus?
Espero que se abra con nosotros.
Espero que se abra con nosotros.
J’aurais aimé qu’il se rapproche
un peu de nous.
Spero che si affezionerà
un po' anche a noi.
Espero que ele se apegue 
 a nós pelo menos um pouco.