Hypnotist's assistant Eric Stein (Jean Sorel) is in love with his boss Han's (Massimo Serrato) fiancée Marta (Eleanora Rossi Drago) and secretly sends her roses every opening night. Chris (Götz George), the guy delivering the flowers, is also an amateur boxer down on his luck and takes advantage of an empty dressing room to steal the trio's bankroll but he's caught by Hans who gets knocked out during a brief struggle. Eric finds the unconscious Hans and bashes his head in with a cane before calling for help as the act's ventriloquist dummy, Grog, seems to look on. The police track Chris to his sister Carmen and chase him out onto a ledge where he saves a detective from falling before fleeing into the night. Now hiding out with his boxing buddies, Chris asks Carmen to help him find the real killer while Marta has a breakdown and the only witness to the crime, Grog, disappears...