It is a perilous profession, similar to the work of a bounty hunter, pursuing oftentimes desperate and dangerous individuals for pay. But with one major difference: Chance Gambel brings in his quarry alive, not draped over a saddle. He is hired to search for witnesses to crimes so that they might testify in trials throughout the frontier territories of the American Southwest, circa 1885. Rarely aware of the consequences of his assignments, Chance has begun to question the merits of his work when he is approached by a Mexican man named Francisco Velasquez and asked to help hunt down Silvano Ramos, the murderer of his sister. Ramos has since become the notorious outlaw leader of a band of cutthroats whose spree of robberies and violence has terrorized communities and small settlements across the western border of Texas. Chance Gambel agrees to Francisco's request as he feels partly responsible for the woman's death: it was he who found her and delivered her to testify at Ramos's trial. So they journey together from Mexico into Texas to confront the murderers -- and each other.