Ricardo is preparing for a dancing party. He invites his good friend Renato's wife Amelia because he loves her. His servant Oscar warns Ricardo that someone will plot to murder him. But Ricardo doesn't mind and he even laughs at the prophecy of witch Ulrika.

At first, Ulrika secretly meets Amelia in her hut. Amelia needs a secret recipe to be able to forget Ricardo. Then, Ulrika tells Ricardo (who is disguised to request for fortune-telling) that he would die at the hands of a friend.

Amelia comes alone to the guillotine to search for forgetting grass at midnight and Ricardo follows her. Both express their love each other. At this point, Renato rushes to notify Ricardo to beware of the assassin. Renato also promises to lead masked Amelia to a safe place. However, the assassin forces Amelia to reveal her identity. Ashamed and angry Renato makes decision to jointly revenge with the assassin. In the Governor's dancing party, Renato assassinates Ricardo, but Ricardo feel remorseful for a long time, and gets ready to help Renato and Amelia jointly return to the United Kingdom. But the big mistake is still made. Before death, Renato proves that Amelia is innocent and forgives all people concerned.