Gunsmoke S20E14 - The Squaw

Matt, in pursuit of three bank robbers, inadvertently catches a fourth one -- their bagman, who swiped the loot and took off. The thieves learn what's happened and go in pursuit of both Matt and the thief. While stopped at a water hole, Matt and the thief meet a group of Indians who are about to leave a squaw in the desert to die. The startled thief asks why and is told the woman is a bad-luck omen, having outlived both of her husbands. To his own surprise, the thief bargains to take the squaw with him and Matt. He doesn't have any regard for the woman, but she proves startlingly helpful when the bank robbers catch up with the group and lay siege to their cabin.