Chaney plays two roles: mad scientist Arthur Lamb and Lamb's "experiment", known only as the Ape Man. This hideous creature was the result of Lamb's attempts to transplant animal glands into human beings.
Lon Chaney
as Dr. Arthur Lamb / The Ape Man
Raymond McKee
as Robert Sandell
Jacqueline Logan
as Angela Marshall
Virginia True Boardman
as Mrs. Sandell
Fontaine La Rue
as Mrs. Lamb
Aggie Herring
as Bessie
Virginia Madison
as Angela's Mother
Wallace Beery
as Beast Man (uncredited)
