Peter is delighted that he is going to live not only with his parents, but also with Jack, whom he was very close to. That is until he has to move to the attic that was waking him up with nightmares to leave his room to the newcomer. But Peter will not give up so easily and gathering his friends will all try to make his grandfather jump, through a series of pranks that are more and more creative. But Jack is not willing to lose and how quickly he declares war on the boy, turning the house upside down. But the question remains: will Peter be beaten in front of his grandfather or will he manage to get his room back, winning the war?