Follows the journey of John and Colt, gunfighters and sometimes lovers, on parallel but very different journeys through an underground dueling culture.

After a young cop gets involved in his third shooting, he is recruited into a special police unit. He quickly learns that the unit is an assassination corps for hoodlums and they don't care who gets in the way. Saving the life of a child gets him a beating by the unit, which they call an initiation. When they raid a mobster's home and start killing hoods and call girls who just happens to be there, he draws a line when he finds one hiding in a closet. He then goes on the run with her with gangsters and the cops both in pursuit.

John Lee is the best hitman money can buy. But when John refuses to kill because of the seven year-old son of his target, John's bosses send someone after John to kill him and then take his place in the ring of hitmen. John then teams up with Meg Coburn to help him escape these "Replacement Killers."