Jim arrives at the territorial prison and the lame Warden Primwick admits that he is as much a prisoner as his prisoners. He assures Jim that prisoner Ralph Kleed will die on the gallows within the hour. The agent notes that Kleed’s threats against the President have made him a greater danger than many, and that there has been a recent outbreak of prison escapes as part of some great conspiracy. Primwick insists that no one escapes from his prison and calls Kleed to his office to make a final statement. Kleed knows who Jim is and tells Primwick that he’s going to apologize and set him free. The warden assumes that Kleed has gone mad, but Jim isn’t so sure.
When Primwick’s pet bird flies past Kleed, the prisoner tries to grab it and Primwick slaps him. As Jim holds him back, Kleed brings out a hidden whistle and silently blows on it. Primwick clutches at his head, and then calls in his guards and tells them to escort Kleed to the gate and set him free. Once they’re alone, Jim asks Primwick what is going on. The warden tells Jim to sit down and relax, and attacks him when the agent refuses. Jim manages to subdue the man, who abruptly dies, and goes after Kleed, only to discover that he’s already made good his escape. The agent finds the discarded whistle on the ground and blows on it, and hears dogs barking in the distant.
Later at the Wanderer
, Artie gets the whistle back from the lab and tells Jim that the pitch has certain special properties. He explains that in the last month, Primwick had a delicte brain operation. A franconium pyrite crystal was found in his brain during the autopsy, and the warden’s doctor knew nothing about the operation. Artie blows on the whistle and they watch as a duplicate crystal first vibrates and then shatters. They realize that the crystal somehow influenced Primwick’s behavior. Jim talked with Primwick’s widow earlier and she reported that her husband complained of headaches three weeks ago after a conference with a territorial governor. They figure somewhere in a hundred square miles, a master surgeon operated on Primwick. President Grant is on his way within a few days and they have nothing to go on. However, Jim suggests that Jim take the place of Carl Storch, the last violent prisoner who has made threats against Grant.
Artie, posing as a guard, is soon transporting Jim by wagon through the territory where Primwick had his operation. Several mounted men, wearing soldier uniforms, come over the rise and approach the wagon. Their leader, Sergeant Stryker, orders Artie to turn “Storch” over to him and draws his gun. Artie obliges and both he and Jim notices that all of the men except Stryker appear mesmerized. When Jim insults the sergeant, Strykes takes out a whistle similar to Kleed’s and blows on it, and the soldiers all aim their halberds at Jim. Jim yanks Styrker off his horse and takes him hostaeg, and forces the sergeant to blow the whistle again and order his men to withdraw. Styrker prepares to shoot Artie but Jim asks to do it instead. The sergeant agrees and Jim shoots Artie dead, and then Stryker clubs Jim unconscious. Once the squad takes Jim away, Artie gets up, removes the uniform jacket over his bulletproof vest, and converts the wagon from a prison transport to a travelling emporium.
Jim wakes up and finds an attractive woman standing over him. He hears explosives going off in the background, and the woman, Josephine, admires his eyes. Jim gets up and discovers that he’s wearing a military uniform, and an explosion shake the chamber. Opening the door, Jim finds himself in a bunker with a man at the window. Outside, a uniformed Kleed is running a gauntlet of explosions. The man, General Titus Trask, informs Jim that Kleed has fear on his side but nothing else. Sure enough, the gauntlet ends and Stryker and his men kill Kleed with their bayonets.
Stryker enters the bunker and Trask congratulates him on the success of the exercise. Trask introduces himself and Jim mouths off, and Stryker strikes him down. Jim knocks him down in response and Trask orders Stryker to leave. The general then compliments Jim on his sterling qualities, but demands that he address him as “sir.” When Trask asks if Jim knows who he is, Jim remembers a Sergeant Trask who was booted out of the Army by General Grant after driving his men to their deaths during desert maneuvers. Josephine comes in and starts rummaging through Trask’s desk, and he explains that she’s his secretary. Trask warns that Josephine is irresistibly drawn to attractive young man, but Josephine denies it and strolls out over Trask’s objections. After an embarrassed silence, Trask goes to the window and watches his men take Kleed away. He tells Jim that he should do better in the gauntlet, and asks what he thinks of his cadre. Jim points out that their machine-like and Trask boasts that his cadre are unstoppable. He explains that each of his men is a murderer sworn to kill Grant, and that he plans to kill Grant when arrives nearby the next day.
Posing as a peddler, Artie follows the tracks that Stryker and his men left.
Trask takes Jim to Professor Frimm, who explains his theory of sonically-enhanced reflex control via the implanted crystals. Once he surgically implants the crystal into the posterior lobe, commands can be given via a special whistle. Jim asks if he’ll be receiving a crystal, and Trask says that he prefers him as-is so he can have him as a second-in-command if Stryker is killed. Once they leave the workshop, Stryker comes in and discovers Kleed on the bed. Kleed tells Stryker that “Storch” is actually Jim West.
Artie spots a flare going off and rides to investigate. At the gauntlet, Trask watches from the bunker and tells Jim that the flare is the signal for the training exercise to begin. As Jim makes his way across the field, Stryker tells Trask that Jim is an imposter and offers to shoot him. Trask tells him that he wants to see how long Jim will last against the cadre, and tells him to give the order to fight to clear. He’s unaware that Josephine is outside the door and has heard the entire conversation.
Jim makes his way through the explosives but comes face-to-face with the cadre. Stryker gives the whistle signal for them to attack. Jim fights them off but one of them sets off a mine, knocking Jim unconscious. Stryker prepares to kill him, but Trask says that he has an idea of a use for Jim.
Artie breaks into Trask’s ranch but a guard intercepts him. After introducing himself as peddler, Artie demonstrates his self-inflating balloons... filled with knockout gas. After tossing the soldier into the bushes, Artie goes inside and starts searching, and Josephine spots him. He offers her a Spanish shawl and fast talk, but she isn’t impressed and threatens to tell Trask. Artie hastily produces a bottle of perfume and pearls, which also fail to appeal. Finally he offers her a portrait frame with a mirror, claiming it’s a picture of they loveliest woman on earth. There’s a sketch of Jim on the other side. When Josephine reacts, Artie realizes that she’s seen him. He claims that Jim has stolen some pearls from him and offers her a box of candy in return for information.
Jim wakes up strapped to a vertical slab in Frimm’s laboratory. Trask comes in and explains that he plans to abduct Grant long enough to have Frimm implant a crystal in him. Styrker comes in, disguised as a cavalry officer, and Trask tells him to send out his men. The general then explains that he plans to have Jim lead the cadre and get close enough to Grant to abduct him. Trask leaves as Frimm prepares to implant a crystal into his brain.
Frimm prepares to administer an anesthetic to restrict his movements, but discovers that he doesn’t have enough cotton. He orders his assistant to get some more, and Artie emerges from hiding to knock the man out. He then knocks Frimm out with the anesthetic and shoves a cart with a scalpel to Jim, who frees himself. He puts a bandage on his head and dons a cavalry uniform, while Artie prepares two large bottles of anesthetic. They find Josephine eavesdropping at the door and they convince her to tell them where Trask and his men are going. Jim and Artie both kiss her on the cheek in thanks and ride out.
Trask and his soldiers are waiting for Grant when Jim rides up. They see the bandage and assume that Frimm performed the operation, and Trask admires his handiwork. He points a gun at Jim and then slaps him, eager to prove that his process has created the perfect fearless soldier. The Presidential party approaches and Trask tells Jim that the cadre have been programmed to follow his orders. Jim mounts up in the middle of Trask’s orders and rides off, and the brainwashed soldiers ride with him, leaving Trask and Stryker behind. They mount up and ride after their men, while Jim leads them to Artie. As he marches them up a hillside, Stryker arrives and uses the whistle to first stop them and then order them to kill Jim. Artie drops the two bottles of anesthetic, which mix and knock out Stryker and his men. Trask arrives and congratulates Jim, and then prepares to kill Jim. Artie calls out to him, distracting him long enough for Jim to attack the general. They struggle on the hillside and Jim finally knocks Trask off the cliff. The general falls to his death and the agents watch as Grant and his party ride by on their way to the territorial governor.
Later, the agents are traveling cross-country and Artie tries to work out his anesthetic formula while Jim reads a newspaper article about how Stryker and Frimm have been sentenced to life imprisonment. Artie is trying to make the knockout gas colorless and odorless. When the Wanderer
slows down, one of the bottles falls into a tray of another liquid. After a few seconds, Artie passes out. Jim covers him with a blanket and congratulates him on his success.