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 shy and affectionate girl who has found new friends and a house in the middle of some ruins of an old amphitheater. But suddenly, a day, the "Grey Men" burst in the city in order to rob people's time. Momo try to stop them but doesn't know how.
One day, Maria meets a prince who gives her a magic stone but then her stepsister steals it and throws it down a well. While trying to retrieve the stone, Maria falls in and awakens in a magical realm.
