At Christmas, three prisoners, Joseph (Humphrey Bogart), Albert (Aldo Ray), and Jules (Sir Peter Ustinov) escape from Devil Island to a French small coastal town. They decide to rob a store, to get some money and clothes and travel by ship to another place. They pretend to be there to fix the roof, but pretty soon they realize that the financial condition of the family Ducotel is not good. André Trochard (Basil Rathbone), the selfish and mean owner of the establishment, exploits the Ducotel family. The three convicts spend Christmas night with the Ducotels and are so well treated by the family, that they decide to help them. Their pet will help them to fix the situation.