After his mother has an accident, obese Julien (14) is taken in by his uncle's family in Switzerland. The family, who to all appearances are totally "normal", make Julien's nutrition and well-being their highest priority. But then Julien falls in love with Keiko, a young Japanese girl. In order to seduce her he pretends to be a Sumo-champion but soon finds himself in a quandary: he needs to lose weight for his new family, but he needs to gain weight if he is going to take part in the Sumo traini...