Back in the days of the frontier railroad, a frantic but deadly Pinkerton named Bill leads a hired posse to the hideout of train robber, murderer, and outlaw gang leader Ned Jingo. As they prepare to ambush the outlaw king, Jingo kills each posse member one by one, leaving Bill to ride through a solid ring of fire in order to survive. Ravaged and enraged by the flames, Bill seeks out his old tracker, Mace. Mace is a rugged half-Navaho who lives off the land and dwells in a cave. Jingo wiped out Mace’s Navaho tribe, and Mace has long believed Jingo to be dead. Upon learning that Jingo still lives, Mace throws in with Bill.