On his way to a post as special adviser of the new parachute troops of the French Foreign Legion in Morocco, Paul Dumont meets the beautiful Helene on the ship. A romance ensues, but the two decide to part when Paul learns that Helene is the fiancée of his best friend and fellow officer Raoul. Raoul is wounded during an Arab attack and the wedding is postponed, and Helene and Paul are thrown together and find it impossible to hide their feelings. The meet in the tent of Hassan, a fortune teller, not knowing the tent is a storage place for arms and ammunition belonging to Addullah, an Arab leader determined to avenge the death of his brother Ben Ali.

Billy, after shooting down land baron William Donovan's henchmen for killing Billy's boss, is hunted down and captured by his friend, Sheriff Pat Garrett. He escapes and is on his way to Mexico when Garrett, recapturing him, must decide whether to bring him in or to let him go.

A demented archaeologist discovers a living, breathing serpent creature known to the Aztecs as Quetzalcoatl and accidentally kills his wife by giving her one of the beast's feathers, causing the creature to track her down and slaughter her. Using this knowledge he exacts revenge upon his enemies by placing one of the feathers on his intended victim and letting the beast loose to wreak havoc.