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.

Jeff Scott is sent to investigate problems with wagon trains attempting to make the journey to Oregon. Sam Morgan has sent his henchmen, under lead-henchman Bull Bragg, to stop the wagon trains in order to maintain control of the fur trade in the area.

Bob arrives looking for the killer of his uncle. When the Sheriff chases him and his partner Rusty, Reno thinks they are the men he is looking for and takes them into his gang. There Bob finds his uncle's gun and knows he has found the right gang. However he realizes the gang has an unknown leader and he sets out to find him.

Learning of Walters' inheritance, Larson kills him and assumes his identity. When Larson's men try to kill Walter's niece Lola, Jack Lane breaks it up. This leads to a showdown with Jack outnumbered by Larson and his gang. Having saved Loma's life earlier, he has Fuzzy ride for him and his men.

Jeff arrives in town to see the Sheriff only to find him just killed. The culprit is Clay Wheeler. When Jeff becomes friendly with Letty, Clay sends his man Ortega to kill him. Jeff foils the attempt and gets him to confess that Clay was the killer. With only old-timers Lafe and Bill to help, Jeff heads after Clay and his gang.

Kalmus is after the freight contract held by Summers. When his gang kill Summers, Tex and Duke step in to help Madge keep the freight line going. When they foil the gang's further attempts, Kalmus gets the Judge to jail the two.

Reporter Terry Brewer goes to the Los Angeles airport to say goodbye to his sweetheart, airline hostess Rita Moore. He notices G-Man Mike Phelan among the passengers and assuming Phelan is on the trail of a criminal, decides to go along to get a story.