Impoverished by his attempt to pay off his creditors after the collapse of his business, Giovanni Rosani moves his family from Milan to Geneva, where they have been promised a home and work by his nephew Massimo. However, the change in fortune causes a split in the family unity, and Giovanni's second wife Giulia and his son Tommy are unable to adjust to their new circumstances. Only his daughter Irene attempts to help him by working as a tutor.
Artistic Giulia soon finds herself romantically involved with a painter, and Tommy, after piling up gambling debts, resolves to marry a rich Russian widow of doubtful reputation. In despair at the disintegration of her family, Irene plans to commit suicide but is prevented from doing so by her father. Instead, she decides to accept the marriage proposal of her cousin Massimo; with him and her father she resolves to confront a new life based on work. The others, like leaves, detach themselves and fall from the "tree."