Dr. Janos Rukh discovers a certain type of radium that has almost magical healing properties. But the element has a dangerous side, too, and it has already started affecting Rukh. Consumed by paranoia, he begins to suspect that his wife is having an affair. Wild for revenge, Rukh hatches a deadly plot...using his own poisoned body as a weapon to kill.
Boris Karloff
as Dr. Janos Rukh
Bela Lugosi
as Dr. Felix Benet
Frank Lawton
as Ronald Drake
Frances Drake
as Diana Rukh
Violet Kemble Cooper
as Mother Rukh
Beulah Bondi
as Lady Arabella Stevens
Walter Kingsford
as Sir Francis Stevens
Paul Weigel
as Monsieur Noyer
Frank Reicher
as Professor Meiklejohn
Georges Renavent
as Chief of the Surete
May Beatty
as Mme. LeGrand (uncredited)
Paul McAllister
as Papa LaCosta (uncredited)
