A circus' beautiful trapeze artist agrees to marry the leader of side-show performers, but his deformed friends discover she is only marrying him for his inheritance.

Gwynplaine, son of Lord Clancharlie, has a permanent smile carved on his face by the King, in revenge for Gwynplaine's father's treachery. Gwynplaine is adopted by a travelling showman and becomes a popular idol. He falls in love with the blind Dea. The king dies, and his evil jester tries to destroy or corrupt Gwynplaine.

Three sideshow performers form a conspiracy known as "The Unholy Three" - a ventriloquist, midget, and strongman working together to commit a series of robberies.