Italy, 1977. Professor Bruschi is a retired widower who lives according to a strict routine he set for himself. An ardent old-style communist, he has always been at odds with the unconventional lifestyle led by his son and his hippieish girlfriend Stella. When their four-year-old daughter is left in his care out of the blue after the two break up, the old professor becomes a sort of father figure to the girl, growing fond of her. However he's once again challenged when Stella also arrives for a stay in his elegant villa, reclaiming custody of her daughter.

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.