Curucu, Beast of the Amazon

In the Brazilian Amazon, after a mysterious, clawed monster claims its fourth victim, workers on a nearby plantation flee to their jungle homes. The local police notify the plantation's owner, American Rock Dean, who learns from his friend, river guide Tupanico, that the Indian workers fear the legend of Curucu, a beast who descends from the Curucu Falls to punish those who have deserted their ancestral lands. Rock returns to Rio de Janeiro to explain the problem to his father, Alfredo Dean, the president of the Brazilian American Trading Corp. Rock proposes that he investigate by traveling up the river to the Curucu Falls, and although he knows the mission is very dangerous, his father is compelled to agree. Before leaving, Rock visits the local doctor for a checkup, and woos beautiful cancer researcher Andrea Romar, who finally accepts a date with him. That night, Rock takes Andrea to a dinner club, where it soon becomes clear that he has dated most of the women in town. Andrea explains that she wants to learn the tissue-shrinking formula used by the jungle headhunters, believing its properties may slow the growth of cancer, but the moment that Rock definitively refuses to take her along on his trip, she leaves. The next morning at the Port of Belem, Rock discovers that Andrea has doubled Tupanico's salary in order to steal his services, and with no guide, Rock is forced to join them in their boat. After passing several menacing crocodiles, they dock to pick up supplies. While trekking through the jungle, they are stopped by Indians, who appear threatening until Rock presents Andrea, hoping her womanliness will prove that they are peaceful. After the Indians check Andrea's body to ensure she is female, they reveal that they are ministering to a sick tribe member. Andrea's healing instincts propel her deep into the tribal camp, where she instantly diagnoses the sick man, Tico, with appendicitis. She rushes him to a nearby mission and operates successfully, earning Tico's lifelong devotion. The next day, Tupanico, who was taken from his chieftain father and reared in the Christian mission, promises to bring Andrea to his tribe to learn their head-shrinking formula. During their travels back through the jungle, a herd of wild buffalo stampedes, and they are forced to hide in the trees. Later, Andrea witnesses a boa constrictor killing a monkey, and narrowly escapes a bite from a tarantula. Rock and Andrea enjoy dinner together in their makeshift camp, but when he grabs and kisses her, she slaps him. Just then, their native porters see a giant, serpent-like shadow in the river, and fearing the fabled beast, refuse to go on. Although Rock wants to return to the city, Andrea refuses, and Tupanico praises her courage. In the middle of the night, Rock creeps into the jungle to search for the beast, not realizing that it has entered Andrea's tent and abducted her. Finally, Rock hears her scream, and tracks them through the trees. He discovers and fights the monster, but it suddenly removes its head, revealing it is Tupanico in a costume, and flees. In the morning, Rock and Andrea try to reach their boat but are stopped by a tribe of headhunters, who truss them and take them far into the jungle, to their village by the Curucu Falls. Andrea, fearing for her life, apologizes to Rock for being stubborn and reminisces about her childhood fantasies of a magical Amazon. They are soon brought before the chief, whom they immediately recognize as Tupanico. He explains that, after years of seeing the white man's ulcers, greed and alcohol, he has returned to his home, where he is considered a god. He offers the formula to Andrea, hoping to help her people, but just then, Tico's tribe appears outside to fight the headhunters. A battle ensues, during which Rock knocks out Tupanico, grabs Andrea and flees from the village. Along the way through the jungle, Andrea is scared by a headhunter, a leopard and a snake, all of which Rock fights off. They finally reach their camp just as a storm begins to rage, and although Andrea sleeps fitfully, she awakes and faints again when she sees Tico. The Indian carries her to the mission, where she wakes two days later. Rock pulls her into his arms, but they are interrupted by Tico, who has brought Andrea both the shrinking formula and the shrunken head of Tupanico.