Down in Old Mexico for a hunting expedition, Jim Sundance ran into an old friend, down-and-out lawyer Jorge Calderon, who was engaged in a lonely battle to save a poor Indian tribe from slavery. The half-breed gunfighter joined the fight against a bloodthirsty Mexican army colonel and ruthless landowner Lucas Bannerman, the mind behind the slave ring. Sundance knew how desperate and dangerous it was to try to fight the enemies of his people.