Having left his friend Mariolino, with whom he had departed for a few days of vacation, in Genoa, the young Giordano Sangalli, son of a Milanese taxi driver, is taken in by three Americans (Sid, art history teacher, his wife Diana and their writer-friend Nelson). They invite Giordano along on their car trip to Tunisia, returning hence to Italy through Spain and the Côte d? Azur. Giordano gladly accepts their invitation, especially after noticing Diana?s interest in him and learning from Nelson that the older Sid leaves Diana totally free when it comes to extra-marital relationships. Once in Africa, Giordano, with Nelson as his accomplice, soon gets the chance to enjoy the couple?s liberal nature, save when it comes to Giordano becoming jealous of a young French hitch-hiker that Diana seems to take a liking to. The trip continues on and the three of them reach the Côte d?Azur. Giordano thinks there?s a chance of him even going on to America, but it?s only a brief illusion. Once in Italy, in fact, the Americans, having grown tired of Giordano, cut him loose immediately.