Lucas Santana is a freelance range detective working for both the US Marshals Service and the Pinkerton Detective Agency in the 1880s. A wanted man in some States, he takes great care where he rides and has a number of off-the-cuff aliases - and is not too shy about lining his own pockets in order to finance his Wyoming Wildcat ranch. When a number of gold coins surface in South Texas, loot from a long ago three-quarters of a million dollar heist at the end of the Civil War, both Pinkerton and the US Marshals call on his services to find the source of that gold. The problem is, he is not the only one searching for it. Then when a fellow agent is murdered in cold blood, Santana's quest becomes personal and he sets off on the long dark trail to nowhere....