BRIDES OF BLOOD

Three Americans arrive on a tropical island: Dr. Paul Henderson, a scientist investigating radiation from atomic bomb tests; his beautiful but sexually frustrated wife, Carla; and Jim Farrell, a young Peace Corps representative. The captain tells his passengers that the island is cursed and is known as "Blood Island". The trio comes upon a funeral procession being conducted by the local natives. The two bodies headed for burial have been completely dismembered. The Americans are greeted by Arcadio, the tribe's elder, and his granddaughter Alma. Alma acts as Jim's interpreter for the natives, but remains secretive about what has everyone on edge.

The villagers choose two of the village maidens to participate in a ritual. The Americans are invited by Goro to visit the home of his master, Esteban Powers, a handsome young man who invites them to stay with him. Jim declines, but Carla insists that she and Paul stay. Esteban suffers from migraines, and reveals that the natives were all moved to the island after the atomic bomb tests; while they seem unaffected by the fallout, the flora and fauna of the island seem to have been altered. The group is startled to discover that the youthful-looking Esteban is actually 50 years old. On their way back to the village, a banana tree grabs Carla with its branches, but Jim and Paul rescue her. A butterfly transforms into a fanged monster and bites Paul on the hand.

In the village, two women are shackled to an altar and stripped of their clothes. Inside a hut with Arcadio and Alma, the Americans hear a strange sound emanating from the jungle, but they are warned not to leave the hut. Outside, a deformed humanoid beast emerges from the jungle and dismembers the two naked women. The next morning, Alma tells Jim that the beast only wants women; the mutilations are its means of sexual satisfaction. She tells him that if they do not continue to sacrifice girls to the creature, it will go berserk and destroy them all.

Paul realizes the animals on the island have the ability to change from their normal state into monstrous forms. The villagers select two more sacrifices by lottery; this time, Alma is chosen. Jim attempts to intervene, but Arcadio and the tribesmen tie him up. At Esteban's house, Carla desires sex, but cannot get her husband interested. She sneaks down the hall to Esteban's bedroom, where she finds him writhing on his bed. When she tries to get into bed with him, his servant Goro appears and forces her to leave the room.

While the villagers await the arrival of the beast, Jim escapes and rescues Alma by firing a flare gun at the creature before it can dismember her. The villagers are furious that Jim intervened, and chase Jim and Alma into the jungle. The duo flee through the monstrous vegetation and return to Esteban's house. Esteban tells them that he and his wife were exposed to radiation during the atomic bomb tests. While he only suffers with migraines, it caused his wife to suffer fatal seizures. That night, Carla sees Esteban stagger out of the house, and she follows him into the jungle, unaware that he is the beast of the island, a transformation he undergoes after each migraine. After an encounter with some monstrous trees and carnivorous plants, Carla is violently dismembered by the monster.

Paul, Jim and Alma search for Carla. Goro chases them with a machete and kills Paul. Jim and Alma find some carnivorous trees devouring what is left of Carla's body. They return to the village, pursued by the monster. Jim convinces the villagers to fight the monster instead of appeasing it. They corner the creature in a grass hut and set it afire. The villagers watch as Esteban, back in human form, stumbles out of the hut and dies. The village celebrates their freedom by holding a love ritual. As the natives pair off and go into the jungle for some wild lovemaking, Alma becomes enraptured by the music as well, and selects Jim as her mate, and the two slip off into the jungle together.

Esteban, revealed to be the mutated beast, dies when he is set on fire by Carla and Paul, ending the cycle of sacrifices. Jim and Alma survive, and the threat to the island's villagers is eliminated.

The ending resolves the central conflict by unmasking Esteban as the product of radiation-induced mutation. His demise through fire signifies both the literal and figurative cleansing of the island's curse. The survivors—the Americans and Alma—mark a return to tentative normalcy, while the destruction of the beast underscores the dangers of unchecked scientific fallout and superstition colliding.