Continuation of Kalimán (The Incredible Man). In the Amazon rainforest inhabits Humanón, who wants to dominate humanity by destroying love, and who has created artificial life in test tubes and performs genetic experiments and brain transplants. The result is the monster and man Perfecthuman. Kalimán arrives to attend a congress of parapsychology with Solin in, Rio de Janeiro, given by Professor Vasco and Xiomara, wife of the late professor Rabadán, who works for Humanón, as he blackmails them with the life of Rabadán and the daughter of Vasco . Kaliman goes to where his enemy lives, fights monsters and finally Humanón.