Inside the hut with Arcadio and Alma, the Americans listen as a strange, overwhelming sound emerges from the jungle, a delirious breathing sound that echoes everywhere. The villagers leave them at the altar and return to their homes. Upon returning to the village, they are not comforted by the sight of the two village maidens being shackled to a remote altar and stripped of their clothing. Jim and Paul fight it off and move her along. The banana trees have moving tentacles that sway when someone passes near one of them grabs Carla and seems to want to kill her. This time, though, it is completely dark outside and the jungle is alive with strange plants. On their way back to the village, the three Americans are escorted once again through the jungle by Goro. Powers seems to not be aware of these anomalies, although the group is startled to discover that he is actually 50 years old his youth seems to have been somehow preserved.

Paul mentions the land crab he found, and the banana tree. Esteban seems to suffer from migraines, and he reveals that the natives were transplants to the island after the atomic bomb was tested while they are unaffected by any radiation, the flora and fauna of the island seem to have been changed. Jim declines due to the nature of his visit, but Carla insists that she and Paul stay in the mansion.

Esteban Powers is a handsome young man who invites them all to stay with him instead of in the village. On the way there, they encounter a banana tree with a strange arm-like growth protruding from it the growth moves as if it wants to seize those who pass by it. Jim, Paul and Carla follow Goro through the jungle until they reach a stately hacienda staffed by a race of pygmies. The Americans are intercepted by a strange looking man named Goro he announces that his master, Esteban Powers, has a table set for them at his home. The villagers participate in another odd ritual: a stylized lottery that selects two of the village maidens for some uncertain fate whatever it is, it causes them to become very upset when they 'win'. Her anxiety worsens when Jim notices a strange plant near the village. Alma acts as Jims interpreter for the natives since she speaks English, but she remains secretive about what has everybody so noticeably on edge. The darkening island becomes ominous, a feeling furthered when Paul discovers the carcass of an oversized crab. Both of them notice a bizarre manifestation when the sun appears to set hours before it should do so.

Paul goes for a walk around the island looking for specimens and is joined by Carla. When questioned about the deaths of the two women that were being buried, he claims the cause was an accident, but he makes the vague statement that his people are 'ashamed' of returning to the 'old ways'. Arcadio welcomes them to the island, but both he and Alma seem terrified of something, and he openly admits that he wishes he would have warned them to stay away before the boat left. Carla immediately senses an attraction between the lovely Alma and the handsome Jim, and she very aggressively attempts to embarrass everyone by remarking on it. After the ceremony, the Americans are greeted by Arcadio, the tribes elder, and his granddaughter Alma. They realize in horror that the two bodies being carried for burial at sea are completely dismembered a dismembered arm falls out, causing Carla to scream in terror.

Upon disembarking, the trio immediately comes upon a funeral procession being conducted by the natives. There are only two stops per year, once every six months. The boat itself is the only one that makes a stop there, with the purpose of delivering supplies. The captain tells his passengers that the island is rumored to be cursed, and is referred to by those in the vicinity as 'Blood Island'. The third American on board is Jim Farrell, a Peace Corps representative who is traveling to the island to help the natives build facilities to better their lives. Accompanying him is his beautiful wife, Carla, who seems to suffer from an extreme case of sexual frustration she makes provocative statements intended to get a rise out of her stoic and seemingly emotionless husband. Paul Henderson is a scientist who has come to the island to investigate the possibility of radiation due to the testing of atomic bombs in the area. The film opens with a freighter approaching a tropical island on board, the captain of the boat has breakfast with his three passengers.

Beverly powers blood island