Lupo has a double who wants to rob an old lady's safe. The children are sailing on their optimist when suddenly a huge yellow submarine appears and swallows them. A visit to Uncle Fax: cousin Ferdinand is supposed to be a role model for F&F, but he is in fact a horror child. Lucky falls in love with the granddaughter of the hated neighbour Old Snotty. Papa and Snotty do everything to prevent this connection.