The crook couple Peter and Gwen have run away from Germany and are dreaming of a sweet life on Mallorca. During a break-in at the villa of multimillionaire Walter Ekland, Peter discovers by chance that the old man is using a detective agency to find his son, who was given up for adoption years ago. Ekland has never seen his supposed last family member and heir and therefore does not know that he has long since died. Peter sees the great opportunity of a lifetime. He assumes the identity of the lost son in order to get his hands on the big money. But the unscrupulous Decker, a private detective who was tasked with finding Ekland's real son, discovers the fraud and blackmails Gwen and Peter...