England. End of the 17^th century.

Mutilated at birth by the Comprachicos (child-buyers), the young Gwynplaine is abandoned by them on a beach eight years later. As the boy is roaming in the frosty cold, he rescues a newborn baby girl who is embraced in the arms of her dead mother. They find refuge with a boorish and solitary carny, Ursus. Ursus discovers the mutilations of Gwynplaine which confer him a permanent smile, as well as the blindness of the infant girl, whose eyes were burned by the cold. At the same moment, while the ship of the Comprachicos is sinking, they throw a message into the sea.

Eighteen years later, Ursus has put on an Act which plays on the contrasts between the infirmity of his son and the delicacy of his daughter, whom he baptized Dea.