The cattle on the Langton Ranch are mysteriously dying and cowhands are disappearing or being shot. Two Langton riders bring a wounded rider they found wounded and hung up in a barbed-wire fence to Sally Langton and report that her father is missing. A lone rider, Jess Ryder, tops a rise and sees a band of men working on some calves in a secluded corral, and he frowns as he sees what Bat Murchinson is doing. Spying Jess, Bat orders his men away and he tries to ambush Jess but is taken captive himself. He takes him to Lynchburg, where Mort Snyder, of the Snyder Land & Cattle Company, is pacing up and down in his office, pondering a cryptic message he has received: "Man from New Mexico heading your way. Dangerous. Watch out." A henchman arrives and tells him that a stranger is bringing Bat to town as a prisoner, and Mort has his men take the sign from over the sheriff's office and put it over his own sign, as the sheriff is out searching for Mr. Langton. Jim Fletcher, Langton's foreman, is watching from across the street and helps Jess elude the trap. Fletcher asks Jess to accompany him to the Langton ranch. When two of Snyder's henchmen accompany Sally's brother, Bob to the ranch in their efforts to purchase the place, Jess and Fletcher make them prisoners and lock them in the cellar, with ranch cook Ching guarding them. That night, Jess takes Hutch, a henchman sent to free the prisoners, and leaves him tied to a tree. Jess then sneaks in and frees the prisoners, telling them that Snyder has sent him and they are to go to the place where Mr. Langton is being held. The next morning, everyone at the ranch thinks Jess has turned traitor. Arriving at the hideout, Jess ties up his two guides, and enters the cabin just in time to keep Mr. Langton from signing a relinquishment to his ranch. Back at the ranch, Fletcher finds the tied-up Hutch, and he and Bob force him to lead a sheriff's posse to the hideout.Jess finds a hypodermic needle which Bat and the other Snyder henchies have been using to inject Langton's cattle with rattlesnake venom, but Snyder arrives and Jess is taken captive. But the posse arrives. Jess tells Sally that he is from New Mexico and has been on the trail of Snyder who has used the same scheme there.