Jim rides up to the small town of Murdock’s Corners as a wolf howls in the distance, upsetting his horse. He manages to calm it, unaware that a robed man is watching from a nearby hillside. Jim goes into the trading post but finds no one inside. The wolf continues to howl and Jim goes out to check on his horse. A wolf leaps at him while the man on the hill gives a wolf cry. Jim’s horse finally breaks its tether and runs off, and Jim gets clear of the wolf and shoots at it, but it seems unharmed and runs away.
Sheriff Twilley rides up, escorting a stagecoach. He tells the driver, Billy, to stay back while he rides in to investigate. Twilley finds Jim at the general store, and the agent explains that he fought a wolf. The sheriff notes that wolves aren’t found in the area, and then confirms that Jim is an agent with the government. Twilley confirms that Prince Stefan is on the stagecoach and will be crowned if he can get back to his country safely. However, the sheriff informs Jim that Stefan wants to visit a town called Luka, and Artie knows about it. The stagecoach arrives and Stefan’s party gets out: Captain Dushan and Dr. Hanska. Artie gets out, disguised as Stefan and acting as a decoy. Finally, Stefan gets out as Artie explains that the prince was kicked out of his own country by his brother the king 15 years ago, and has been working as a date farmer in Arizona. Now that the king has died without any heirs, Stefan is the rightful ruler.
Artie presents Jim to Stefan and says that they’ll be staying at Murdock’s Corners for the night, and that they’ll arrive at Luka before noon the next day. Stefan notices that Jim was attacked by a wolf. Stefan’s daughter Leandra Novokolik gets out of the stagecoach, and Stefan insists she start preparing herself to be a princess. Meanwhile, the man on the hillside slips away into the shadows.
The royal party enters the grocery store and Twilley says that the owner, Sam, should be around. As the sheriff takes Stefan and his party upstairs, Artie explains that some of Stefan’s countrymen are in Luka and he wants a local priest to perform the coronation rites. Stefan comes down and says that he’d prefer to be a date farmer, but he has obligations to his country. He asks about the wolf and Jim explains that he shot it but nothing happened. Stefan says that he wants to follow the blood trail and make sure that the wolf is dead. The trio follows the trail and finds the dead wolf. They also find the storekeeper, Sam Murdock, dead. His throat has been torn out but the marks aren’t those of any known wolf. However, Stefan says that there is one known type of wolf with the necessary claws.
The robed man, his right hand replaced by a metal claw, watches from the shadows and strokes one of his wolves.
The agents bury Murdock as the wolves howl in the distance. Artie has found a book about lycanthropy in the stagecoach and Jim reads a passage men transform into wolves on the full moon. They hear Leandra scream and run to investigate. She tells them that she saw an animal in the woods. The agents investigate and find Jim’s horse. As Artie goes back to the general store, Leandra apologizes and then takes offense when Jim calls her “princess.” She insists that she’ll be a prisoner and forced to marry a foreigner. Leandra breaks into tears and Jim compliments her as a beautiful woman.
Jim and Leandra return to the grocery store, where Artie has noticed a flashing light in the distance, signaling a single word in Morse code: “Vrkalak.” Stefan overhears Leandra saying that he’s used the word and orders her to bed. Once she’s gone, Stefan tells Jim to take him to the light, and that it means someone is in great distress. Stefan insists on going, ignoring the agents’ advice, and they goes with him. Meanwhile, Artie asks Dushan what “Vrkalak” means, but the captain claims he’s never heard of it before.
Leandra is in her room and Dushan stands watch outside in the hallway.
Stefan and the agents dismount and approach the light source on foot. The king loads his revolver with a large-caliber silver bullet and explains that he’s kept it for 15 years, for a man named Talamantes. When Jim wonders if Talamantes wants to keep Stefan from taking the throne, Stefan explains that Talamantes wants him to have the throne... under his control.
One of Talamantes’ men enters Leandra’s room and captures her.
The agents find a lamp and Stefan says that it’s an obvious trap, but he wants to settle things once and for all. Talamantes calls from the shadows, asking for a truce. Stefan grants him five minutes and Talamantes steps forward. He urges Stefan to renounce the throne, but Stefan is well aware that he controls one or more of those in the line of succession. Stefan refuses, knowing that Talamantes controlled his brother. Talamantes warns that he has Leandra, and Jim points out that they have Talamantes. A wolf leaps out of the woods and attacks Jim, and both agents fire on it without effect. Stefan shoots it with the silver bullet, driving it away, and Stefan insists on going back to check on Leandra.
When the trio returns, they discover that someone overpowered Dushan and took Leandra. Stefan wants to ride out but Jim refuses to allow it. The would-be king reluctantly accepts Jim’s orders, but then collapses from a stroke. Hanska tends to him and informs the agents that Stefan had a stroke two weeks ago. Jim figures that Stefan wanted to be crowned in Luka because he wouldn’t survive the trip home, and that Stefan wanted to make sure Leandra was his successor. Hanska tells them that Stefan won’t survive the journey and only has a few hours at best. Artie suggests that he ride to Luka and bring back the priest. Jim agrees and Artie takes the stage while Jim goes after
In an abandoned mining tunnel, Talamantes prepares a syringe to give Leandra a serum that will let him control her mind. He admits that he can’t dominate Stefan without a lethal dose, but it will work on those with a lesser will. Leandra insists that she’s her father’s daughter as Talamantes gives her the injection. He tells her that when she awakens, she’ll have no memory of what happened until she hears or reads the word “Vrkalak,” and then she will obey his every command.
Jim rides back to where the signal lamp was used and follows the trail to the mining tunnel. He gets the drop on one of Talamantes’ men and knocks him out.
Artie rides back to Murdock’s Corners with the priest and other people from Stefan’s country.
Jim enters the tunnels and finds Leandra. She has no memory of what happened or who Talamantes is. Talamante returns as Jim hides in the shadows. He claims to be a loyal countryman and Leandra tells him to raise his hands as Jim emerges from the shadows, gun ready. Talamantes points out that he has broken no laws, and Leandra is forced to admit that she doesn’t remember how she was kidnapped. Jim takes Talamantes out anyway only to discover two wolves waiting for them. Talamantes explains that his serum makes his wolves nearly immune to pain and injury, and then says the word “Vrkalak.” Leandra picks up a timber and knocks Jim out from behind.
Artie arrives at Murdock’s Corners with the stagecoach and tells Hanska that he’s brought the priest. Hanska tries to rouse Stefan, who wakes up and asks about Leandra. Artie assures Stefan that his daughter is fine.
Jim wakes up and finds a wolf guarding him. He drives it off with a smoke grenade and jumps into a mine cart. As he shoves off, another wolf leaps into the cart. More wolves pursue and Jim manages to toss the wolf out as the cart emerges from the tunnel and an explosion seals the entrance.
At the grocery store, the priest and his people have set it up as a makeshift chapel. Dushan and Hanska escort Stefan in as Artie and Twilley look on. Stefan is placed at the altar and the priest begins the ceremony. His men place Stefan on the throne just as Leandra arrives. Artie goes to her and she claims that she hasn’t seen Jim, and is unable to explain how she got away. Hanska ushers her over to Stefan, who realizes that she has fallen under Talamantes’ spell. He tells his men not to crown him, but the priest proceeds with the coronation. Jim arrives and says they have to stop, but Artie realizes that they’ve crowned a dead man. Dushan declares Leandra the queen.
That night, the agents and Leandra depart in the stagecoach. She asks why her father tried to stop the coronation, and Jim explains that Talamantes has hypnotized her. They arrive at the Wanderer
and Leandra agrees to meet with the reporters for five minutes. She then asks Jim to break the spell before she returns home and is beyond help. Artie has an idea and tells her that she’ll have to do exactly what they say.
The reporters enter the car and Leandra reads from a prepared statement, telling them that she is abdicating. The agents escort the reporters out, while Dushan takes a card out of his jacket and places it on the table. Once he leaves, Jim tells Leandra that Talamantes will have to come and reassert control over her and have her accept the crown. Leandra checks Dushan’s card and finds the word “Vrkalak” and instructions to kill Jim. She takes Jim’s gun and aims at him, insisting she has to kill him. Artie, disguised as Stefan, steps out of the back.
Talamantes, Dushan, and a henchman are waiting outside and hear the gunshot. They go inside and find Jim on the floor, dead. There’s no sign of Leandra, but Talamantes is confident that she’s under his control. Artie steps out, still disguised as Stefan, and Dushan shoots him. Artie takes a bullet in the shoulder and Jim shoots Dushan. He disposes of the henchman and Talamantes attacks him with his metal claw hand. Jim finally knocks him out and Talamantes falls on his own claw. The agents realize that the silver bullets were effective against the wolves only because they were such a large caliber. Leandra emerges from the back and Artie apologizes, explaining that he had to pose as Stefan to shock her out of Talamantes’ spell. She forgives him and Jim says that it’s time for her to take the throne.