Many returns to Casa Martini: Guido has returned from his experience in Africa, Lele returns with his twins. Cettina and her family are absent: the Martini family's former housekeeper has apparently disappeared in a shipwreck. A nasty surprise awaits Guido and Maria: they discover that their apartment's tenant refuses to return the keys. During a chat, Grandpa Libero reveals to Lele that he's feeling the weight of old age.