Basil and Gertrude Jethro are a married couple of brillant surgeons. When Basil takes out an insurance on Gertrude's life, she decides to murder her insane husband first. They change identities via plastic surgery and Gertrude can pose as Basil and cash in on the insurance money.
The murder victim Frank Lee visits the town in the guise of his nox-existing twin brother Walter. With the aid of black magic he avenges his death and finishes off his three killers.
Two killers stow away on a freight ship to Africa. When one of them needs his appendix to be removed, they force the ship's doctor to do so. The doctor is killed afterwards, but he left a surprise in the gangster's stomach.
Henpecked husband Charlie Noonan constructs an explosive alarm clock to murder his wife. When the bomb goes off, he himself is felled by a deadly heart attack.