On this way to his partner's ranch, Glenn Oliver runs into a posse chasing Joe Thomas. When the posse shoots and kills Thomas, Glenn is warned by sheriff Bart Widner that horse thieves and murderers are treated that way in this area. Farther down the road, Glenn finds Judy Walton struggling to free a calf stuck in a fence. Glenn helps her and they are quickly attracted to each other, but when Judy learns that Glenn is headed for the Bar W ranch, her disposition quickly changes. Back at the Walton ranch, the Bar V, Joe Walton, Judy's father, is informed that more of his horses are missing, and his foreman, Carter, suspects they have been rustled by the Bar W. At the Bar W, Glenn finds his old friend and partner, Jim Perkins, in distress, as he cannot understand how his herd of horses keeps increasing. Cattle baron Pete Hadley arrives to tell Perkins that horses have been rustled from the Bar V and the sheriff is on his way to check Perkin's stock. Just then, Walton and his men arrive and accuse Perkins of rustling. When Walton tries to lynch Perkins, Glenn steps in and threatens to kill him if he tries such a thing again. In actuality, Carter has been rustling the horses for Hadley, who hopes to force both the Bars V and W to sell out to him. As Glenn checks the Bar W for rustlers, a sniper takes a shot at him, but misses. In the vicinity of the shot, Glenn captures Judy, who claims she was only chasing a baby black bear. Glenn returns to the Bar W, only to find Perkins dead of a gunshot wound to the head. Glenn scouts the area and find shells from the murderer's gun. An "old-timer" sees Glenn, and when Glenn asks what he is doing there, the old-timer tells him that he is "looking for a little black bear." Glenn goes to the Bar V, where he warns all that he plans to avenge Perkins' death. He checks Walton's gun and discovers it is the one that killed Perkins, but, because of his attraction to Judy, he does not tell the sheriff. The sheriff holds an inquest into Perkins' death, but discovers nothing. Judy tells Glenn that she found her father's gun after the shooting and swears that she and her father are innocent. As Glenn rides back to the Bar W, he is attacked by a vigilante group who accuse him of being a "range detective." Glenn is rescued from the group by the old- timer, who claims to still be looking for the "little black bear." Back in town, Glenn searches for the vigilante he wounded in the ambush. When Bart Green tries to escape, Glenn captures him just outside of town, but before Bart can tell Glenn anything, he is killed by another sniper's bullet. Back at the Bar V, Walton prepares to go into hiding, thinking that Judy killed Perkins with his gun. When Judy confronts him, they both realize that the gun was planted, just like the stolen horses. Hadley arrives with the sheriff, who is forming a posse to go after Glenn for Bart's murder. Judy rides off to warn Glenn, who barely manages to leave the Bar W before the posse arrives. Glenn is trapped in a mountain pass by the posse, and when all looks hopeless, the old-timer appears to help him out. Just as the posse is about to blow Glenn off the mountain with dynamite, Judy and Walton arrive. Glenn hears Judy's voice, stands up, and is shot. The old-timer then steps forward, telling everyone that he is the "cow detective" they are looking for and that Carter is the murdering sniper, not Glenn. As Carter goes for his gun, he is killed by the old-timer. Hadley, realizing the gig is up, grabs Judy as a hostage, but as he walks down the mountain, he trips and falls. Glenn, who was only slightly wounded, runs after Hadley and captures him after a fierce fistfight. With the rustling and murders now solved, Glenn and Judy ride off together.
