Toni Sommer (68) used to be the most popular and successful "Schwinger" of his time in Switzerland's traditional wrestling sport, but since the fatal accident of his opponent and best friend, he's been living anonymously and lonely in a suburb of Bern. His energy and his zest for life have left him, and the only friend he has is the grave of his former opponent. Hiro, a 10-year-old boy, disturbs Sommer's reclusiveness. He lives with his grandma one floor above Sommer's flat. Hiro is a short, thin boy who is a highly gifted student in school. However, Hiro wants only one thing - to become a great sumotori, a sumo wrestler. When his grandma dies unexpectedly, Hiro pleads the grumpy Sommer to take him to a sumo stall in his home country, Japan. Sommer is not interested, but he finally overcomes his initial resistance and accepts the deal. As soon as they arrive in Tokyo Sommer has to decide whether to engage in the boy's dream or to cancel the trip at an early stage, because he learns why the boy has chosen a Sumo school on an island in the far south of Japan - the boy's father used to be a student here and Hiro wants to follow in his footsteps. And so a journey starts from Tokyo across the country to a harbour city from where they will take the ferry to Amami Island. The film tells - in a humorous and touching way - the story about the struggle between the two unequal and different characters and how they finally become grandfather and grandson, developing a deep friendship.