In the 19th century, a bizarrely disfigured harpooner named Iguana Oberlus (Everett McGill), suffers abuse from peer sailors on board of a whaling vessel. One night he escapes and continues to live on a remote island of the Galapagos Islands. There, he proclaims himself the ruler of the island and declares war on humanity. Anyone who happens to find himself on the island faces the cruel tyranny of Iguana. He enslaves shipwrecked sailors, and Carmen (Maru Valdivielso) is forced to become his mistress.