Gregg Palmer as Kimo, the island prince, watches his people suffer from a spreading plague on a remote South Seas isle. He is accused of murdering his father, the island chief, with a poisonous medicine supposedly supplied by a group of American scientists stationed at a field lab. The truth appears to be far more brutal: the real murderers are Robert Swan as Tano, a witch doctor, and Baynes Barron as Chief Maranka, who condemn Kimo to death by a knife thrust into his heart. Kimo pleads with his wife Korey, played by Suzanne Ridgway, to prove his innocence, but she refuses. He swears vengeance on Tano, Korey, and Maranka, and after the execution he is laid to rest in a hollow tree trunk, a stark symbol of the island’s dark fate.
Tina Carver stars as Dr. Terry Mason, the American physician arriving to help study and treat the plague-stricken natives. She is warmly greeted by Tod Andrews as Dr. William Arnold, and the two meet with John McNamara as Professor Clark. Terry is introduced to Linda Watkins as Mrs. Mae Kilgore, who runs a trading post on the island. Also present are Lee Rhodes as Norgu and his wife Lenmana Guerin as Dori, who is recovering from the plague and suffering faint radiation burns caused by nuclear fallout from a nearby atomic blast. The scene broadens into a portrait of a community caught between ancient beliefs and modern science, where every new piece of information shifts the balance of trust.
Later, Terry and William stumble upon Kimo’s grave and a tree stump growing from it. Lee Rhodes as Norgu recounts a local legend about a returning chief who binds his spirit to a tree monster—the Tabanga. The scientists determine the stump is radioactive and pulses with life. They remove it and bring it to the laboratory, where its heartbeat weakens. Terry injects a specialized formula to keep it animated, and by the next day the figure—now the Tabanga—escapes from confinement. The Tabanga is a living relic of the island’s past, a terrifying reminder of how closely myth and science can collide, and it is introduced on screen as the legendary creature Chester Hayes as Maku / The Tabanga.
Jealousy gnaws Korey as she watches Maranka favor another woman, Naomi, played by Tani Marsh. Korey lashes out with a knife, but the encounter unleashes the Tabanga’s fury. Naomi flees as the Tabanga methodically targets Korey, throwing her into a pit of quicksand. Korey perishes, and the monster then tracks down Chief Maranka, throttling him to death. The islanders, fearing further bloodshed, urge the scientists to confront the terrifying revenant.
Tano and the native partisans lure the Tabanga into a pit and set it aflame, but the creature smolders and rises again, turning its wrath toward Tano as it hurls him down a slope, where he is impaled on a woody plant below. The search party finally closes in on the Tabanga, and Eddie, the American named Mark Sheeler, fires at the creature as it drags Terry toward the quicksand. A lucky shot hits the knife still lodged in the monster’s chest, driving it deeper into its heart. The Tabanga sinks into the quicksand and dies, its menace extinguished for good. William and Terry share a quiet embrace, while a native onlookers asks Professor Clark John McNamara if he would be willing to take Tano’s place as the island’s new witch doctor, closing the circle between fear and possibility and leaving the door open for a fragile hope to return.
