The story is set in the American West in 1880, after the end of the Civil War. Isabella, once a young outlaw, follows the dying wish of her mentor Ron Taylor and plans to leave her past behind to become an ordinary locksmith, but a dispute over a treasure drags her back into the underworld. She meets Micah, a master-of-disguise thief who is neither wholly good nor wholly evil, and the two alternately compete and join forces to investigate a federal payroll gold robbery from twenty years earlier. As the clues unravel layer by layer, the Soren crime family, the Gray Feather thieves' gang, and a greedy politician and his mistress all enter the picture. Struggling between revenge, truth, and morality, Isabella ultimately completes her mentor's unfinished mission and holds fast to the righteous path in her heart.