Straker flies to San Paulo in Brazil to check on seemingly inefficient South American operations there. Met by Lieutenant Gomez at the airport, Straker is suddenly hit with a blowpipe dart from a disguised native indian, and collapses - dead! Foster flies out to the SHADO base there to investigate, and notices that the glass panel in the coffin lid is misting over - Straker is alive but in a deep suspended animation. The dart had a nerve-paralysing poison unknown to mankind, but the indian had been killed trying to escape. He is recognised by Major Enchada as a Curura indian - a primitive tribe no white man has ever visited. SHADO scientists may be able to find an antidote but another twenty-four hours and Straker may suffer permanent brain-damage. Foster has little choice but to take Enchada and Straker's body by Mobile up the Rio del Muerte river, to find the indians and a possible cure. Hours later, they spot two indians spear-fishing in a canoe, but Enchada's clumsy handling of the Mobile capsizes it. The man is saved but Foster has to fight an alligator to save the boy. This puts the two indians in their debt, and using sign language Foster is able to explain their need.