Lorrimer Weldon has spent his life being a tumbleweed and rolling where the wind blows him. Up to Canada, down to Mexico, through deserts, forests, and mountains; anywhere fortune could be found. Those travels helped earn him a reputation as a gambler and a gunfighter-a reputation that frequently preceded him.

When Weldon rode into San Trinidad, he found he immediately had two job offers: the outlaw Roger Cunningham wants Weldon to join his smuggling operation as a hired gun, and Dr. Henry Watts wants to hire Weldon's gun as well, but as muscle to protect a patient dying of consumption, the beautiful Helen O'Mallock.

Weldon finds Watts' proposition far more attractive, so he accepts the offer, knowing that Cunningham will resent the decision.