It's Christmas Eve in Naples. Little Rocco feels increasingly jealous due to the imminent birth of a baby brother. Three bungling devils sent by Satan promise him that if he'll stop Jesus from being born—entering the Nativity scene his father built by the magic word "opopomoz" and altering the past—his brother won't be born either.

Momo is a young orphan girl who lives in the ruins of an old Roman amphitheater and becomes friends with everybody in the neighborhood. But when a powerful international corporation starts stealing everybody’s time, nobody has any time left for her, let alone their friends or families. Momo, together with Master Hora, the custodian of time, are the only ones who can go up against the time thieves before all is lost forever.

The story is set at the beginning of the 20th century in Sicily. Salvatore, a very poor farmer, and a widower, decides to emigrate to the US with all his family, including his old mother. Before they embark, they meet Lucy. She is supposed to be a British lady and wants to come back to the States. Lucy, or Luce as Salvatore calls her, for unknown reasons wants to marry someone before to arrive to Ellis Island in New York. Salvatore accepts the proposal. Once they arrive in Ellis Island they spend the quarantine period trying to pass the examinations to be admitted to the States. Tests are not so simple for poor farmers coming from Sicily. Their destiny is in the hands of the custom officers.

Oscar, an adorable and bizarre alien from Pianota, the planet of Music, is forced to land on Earth due to a malfunction in his spaceship. Here he befriends Tommy, a brave and charismatic 10-year-old boy who receives a series of ultra-technological gadgets for each mission from his inventor uncle, Prof. Leonard. The two, united by their passion for music and love for all races, experience exciting adventures together in every corner of the world, solving mysteries and saving people in danger.