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"...
Oh, by the way, we heard 
Takashi-san remarried.
Ach, übrigens, Takashi-san
soll wieder geheiratet haben.
Por cierto, escuché que 
Takashi-san volvió a casarse.
Por cierto, escuché que 
Takashi-san volvió a casarse.
Ah, j’ai entendu dire 
que Takashi s’est remarié.
Ah, abbiamo sentito
che Takashi si è risposato.
Ah! Se não me engano o Takashi-san
se casou novamente, não é mesmo?