Unknown to Joan Manning, her trading post partner Weathers is operating a counterfeiting ring. When miner Jim Smithers brings his gold dust in, Weathers pays him off in counterfeit money. Jim's drunken brother, Bill, comes to the post and Weathers hears him say that Jim is leaving the area for good. Weathers sends Hawks to kill Jim and retrieve the bogus money. RCMP Sergeant Renfrew and Constable Kelly find Jim's body, and Renfrew hurries for Jim's cabin to search it. He is attacked by Weathers' men who have found the money. Renfrew is suspicious when Bill Smithers body is found, supposedly a suicide, with a note he had burned the money. This leads the Mounties to suspect counterfeiting. Kelly follows Manti, an Indian who works for Weathers, to the gang's hideout and is captured. But Renfrew is trailing Kelly.

Renfrew of the Mounties hunts brother-and-sister gold hijackers.

Sgt. Renfrew and Constable Kelly go aloft to search for a plane missing with a shipment of gold from the Yukon Mine Company. Inventor Speavy has devised a power ray which disrupts electrical impulses, and Morgan and his gang of crooks has brought in Prof. Lewis to increase the ray's range, telling him he's helping the government develop this new weapon. Speavy spills the beans to Prof. Lewis and his daughter Madeleine,and Morgan threatens to implicate them in his crimes unless they cooperate. Morgan kills Speavy when he tries to warn Renfrew, but when Madeleine stows away on board the doomed plane Renfrew is piloting, will the crooks be able to make Prof. Lewis use the power ray to bring the plane down?

The Royal Mounties are called in when one of the armored cars owned by Maxwell, containing a gold shipment, disappears with driver George Hill suspected of trying to get away with the gold. Actually, Maxwell and two henchmen had poured acid on the brake lines, causing the car to crash. Genevieve, daughter of the Mountie chief, suspects Maxwell and Thomas Hatch, president of the bank shipping the gold, but she quickly becomes more trouble than help to Sergeant Renfrew in charge of the investigation. Renfrew and Constable Kelly drive the next shipment but Maxwell plans to make them crash the same way as Hill did. Renfrew steers the vehicle into a hillside and this gives him an idea of what happened to the other car.

Death stalked Garou's Landing, in the Canadian frozen north, but who was the killer who murdered two men and left them huddled in the snow. Sergeant Renfrew (James Newill, of the Royal Canadian Mounted Police, accompanied by his dog, Silver King (Silver King the Dog), and Kay Larkin (Terry Walker) the daughter of the man, Andrew Larkin (Robert Frazer) accused of the crime, sets out to solve the crime and bring the real killer to justice.

Ann Fenwick is a witness to a bank robbery in the U.S. and the bandits, led by Trigger and Leon capture her and when she disappears, a warrant is issued for her arrest as a material witness. The bank robbers flee across the border into Canada where they steal a trailer in which they lock Ann and the loot. The hitch breaks and the trailer plunges into a lake. Sergeant Renfrew and Constable Kelly, of the Canadian Mounties, rescue Ann and she tells them she is a hitch-hiking tourist and gives a false name. Renfrew sends Kelly for aid, Ann escapes and Kelly returns with the news that she is wanted. The leader of the gang, Cardigan, sends the gang back for Ann and the loot, which Ann has hidden in a trappers cabin, just before Trigger recaptures her. Renfrew goes to her rescue, but is also captured. But reliable Constable Kelly is somewhere in the woods.

When the plane owned by the "Yukon and Columbia Mail Service" crashes, RCMP Sergeant Renfrew (James Newill) and Constable Kelly (Dave O'Brien) suspect murder. Their suspicions are confirmed when Renfrew finds the control stick has been jammed, forcing the plane to fly in one direction until the gas ran out. Mine owner Louise Howard (Louise Stanley) reports that her superintendent is missing. The Mounties find him murdered and that too has been made to look like an accident. A new mail service pilot, Bill Shipley (Warren Hull), arrives. He had gone to training school with Renfrew but had been cashiered for misconduct. The Mounties discover that Raymond (Karl Hackett), who had been working for Louise, really owns the flying line managed by Yuke Cardoe (William Pawley.) They find proof that all the gold from the mine isn't being turned over to Louise, and suspect that Raymond and Yuke are stealing the gold and shipping it to Seattle by plane.

Counterfeit bills are being printed in Canada and shipped across the border hidden in blocks of ice. When the counterfeiters force engraver Bronson to make a new plate, he inscribes a tiny help message on it. Renfrew catches a henchman who has one of the new bills. A magnifying glass lets him read the message and he heads out alone to round up the counterfeiters.