Belleville, 1963. Alain, a boy of 10 years old, lives alone with his mother in the village. In the Rue des Cascades, they have a grocery shop. Alain’s life is about to be turned upside down: his mother has a new, black lover, Vincent. This is not an arrival Alain expected, and motivated by racism and jealousy, he decides to shut the newcomer out. Through Vincent’s enormous heart, kindness and patience, he wins Alain over to be his best friend. But Alain’s friends certainly won’t think so…