After a baron steals his scientific discoveries, runs away with his wife, and slaps him in public, a man joins a Parisian circus sideshow as a clown whose act consists of being slapped repeatedly and becomes infatuated with a showgirl colleague whose father intends to marry her off to the baron.
Blizzard, deranged from a childhood operation in which both his legs were needlessly amputated after an accident, becomes a vicious criminal, and eventually mob leader of the San Francisco underworld.
Francis, a young man, recalls in his memory the horrible experiences he and his fiancée Jane recently went through. Francis and his friend Alan visit The Cabinet of Dr. Caligari, an exhibit where the mysterious doctor shows the somnambulist Cesare, and awakens him for some moments from his death-like sleep.