 Vincenzo Scognamiglio steals a pineapple jam jar in the Naples harbour and he is really astonished when he finds his mouth full of golden coins. His wife Maddalena realizes at once that the coins are part of the booty of a robbery which had taken place in New York and for which Joe Castagnola is the main suspect. So Vincenzo and Maddalena decide to contact Joe and to help him in getting back his loot. But in the meanwhile the Commissionar Di Savio and his assistant, La Nocella, are questioning Castagnola about the missing golden coins.