Jack Rock, a deputy of the Cattleman's Association, infiltrates a prison and learns from inmate Clink Peeples to contact Ash Preston in Wagon Tongue if he wants to join up with cattle rustlers. Jack "breaks out" of jail and, impersonating outlaw Jim Collins, saves Ash's life in a barroom brawl, for which Ash promises him a job on his ranch. On his way to the ranch, Jack helps Ash's sister Jane with her lame horse. Later, John Hesbitt, head of the rustlers, reprimands Ash for getting drunk with a stranger and informs him of his plans to set Kettle Valley on fire to force rancher Williams to herd his cattle through Sunset Pass, where they can be easily stolen. Ash does not want to be involved in this scheme, but Hesbitt has been blackmailing him with the knowledge that Jane is not really his sister, which Ash hopes to keep from Jane. One night Jack sees Ash talking with a rustler and follows Ash the next day to the rustler's hideout. There, after proving that he is Collins by performing a card trick that Collins is renowned for, Jack is accepted by the rustlers. Hesbitt later reveals to Ash that he, not Jack, is really Jim Collins, and both men become suspicious of Jack. In the meantime, Jack has returned to the ranch to warn Jane that he will not press charges against Ash if he stays at the ranch during this next raid. Jack forewarns Williams and they conceive of a plan to stampede the cattle to surprise the rustlers. The plan works and Hesbitt is shot. Jack fights with Ash and offers him immunity, but is forced to defend himself and shoot Ash. Before he dies, Ash asks Jack to burn the papers in Hesbitt's cabin relating to his family history and never to reveal the truth to Jane. Jack agrees, realizing now that Ash was blackmailed into helping the rustlers, and Ash dies, knowing that Jane is safe with Jack.