In the nightmarish last days of the Third Reich, a psychotic Nazi scientist (Robert Vaughn, Bullitt) escapes to the impenetrable jungles of the Amazon. Years later, a mysterious incurable disease breaks out among the natives and adventurer John Hamilton (Michael Dudikoff, Avenging Force) is hired to lead investigators on a search for the cause. Braving bloodthirsty rives pirates, hostile native tribes and headhunting cannibals, Hamilton, guides a group of explorers up the deadly Rio del Morte to the fabulous lost Inca city. Action specialist Steve Carver (Lone Wolf McQuade) directs this top-notch action-adventure based on an Alistair MacLean (Breakheart Pass) novel. The stellar cast includes Donald Pleasence (Wake in Fright), Herbert Lom (Golden Salamander) and L.Q. Jones (The Wild Bunch).