Tommy Markham, the young son of American engineer working on a dam project on the edge of the Brazilian Rain Forest, is abducted and adopted by a primitive tribe. The father, Bill Markham, spends the next ten years searching in vain for the kidnapped boy. Ultimately Markham is captured by a cannibal tribe and ironically rescued by “Tomme,” who only has dim memories of his biological father. Although Bill wants desperately to have his son accompany him back to civilization, “Tomme’s” loyalties now belong to “The Invisible People.”