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"...
make up some lie about 
being on the verge of death
die man nicht kleinkriegt, dazu,
una mujer que no moriría ni en cien años,
que no moriría ni en cien años,
Je suis venu parce qu’on m’a dit
una donna che nessuno
riuscirebbe mai a uccidere,
que provavelmente não 
 morreria nem se te matassem, 