When Philo Vance's dog does not make it into the final of the Long Island Kennel Club's Conformation show, fellow competitor Archer Coe (Robert Barrat) is disappointed, having hoped to savor a victory over Vance. The next morning Coe is found dead, locked inside his bedroom. District Attorney Markham (Robert McWade) and Police Sergeant Heath (Eugene Pallette) assume it was suicide, because Coe was shot through the head and was found holding a pistol. Vance is not convinced. He soon finds evidence that Coe was murdered. Coroner Dr. Doremus (Etienne Girardot) determines the victim had bled to death internally from a stab wound.