Sergeant Cassidy, of the Canadian Mounted Police, is not pleased when his commanding officer, Inspector Reed, orders him to train a new arrival, Corporal Robert King, the commissioner's son, who has a reputation as "the Beau Brummel of Ottawa." Cassidy gives King pointers concerning the sport of "balaklava melee," in which two mounties on horses face off against one another to retrieve the plume on the helmet of the other. King proceeds to throw Cassidy off his horse and get his plume, and then sends Cassidy a newspaper clipping about his exploits as the balaklava melee champ of Ottawa. After King later mocks and taunts Cassidy, Cassidy orders King to fight and knocks him down. Impressed with Cassidy, King tears up a clipping in his scrapbook which shows him as the mounted police boxing champ. When Reed assigns Cassidy to search for furs stolen from a trading post in an incident in which a watchman was killed by a dog, King convinces Reed to allow him to go along, even though Cassidy objects. Reed wants Cassidy to search the lodge belonging to Jim Alison, whose daughter Jean earlier rebuffed King's attempted flirtation. When Cassidy and King arrive at the lodge, Alison's partner, Ray Jennings, orders his men to hide the stolen furs in the root cellar. After Jennings leaves in a plane, Cassidy notices Jean's dog Buck, who earlier attacked King, sniffing at a spot in the root cellar, while King is preoccupied apologizing to Jean for the search. Cassidy warns King that duty and a pretty girl do not mix, and then locates a hidden door in the floor of the cellar. They find the furs and arrest Alison, who confesses to his daughter in private that he has been involved in smuggling furs across the border to avoid paying taxes on them; however, he says he did not know that the furs were stolen and thinks that Jennings also may not have known. He convinces Jean to help him escape, so that he can meet Jennings at the cabin of their compatriot Donaldson and find out how much Jennings knows. Jean diverts King's attention with a kiss, and with the help of their Chinese cook, she and her father escape on Cassidy and King's sled. After Alison and Jean split up, Cassidy sends King to follow Jean while he hunts for Alison. King finds Jean by a campfire, and she becomes annoyed when he makes friends with Buck. After he goes to sleep, Jean tries to sneak off with Buck, but King has tied a rope to Buck and attached it around his own wrist. He carries Jean back and after handcuffing her to him, makes Buck sleep between them. When Alison finds bales of stolen fur at Donaldson's cabin, Jennings sicks his vicious dog Wolf on him, and then leaves Alison to die as he and Donaldson search for Jean to kill her. When King becomes lost, Jean refuses to help, but after he protects her from a snow slide and injures his leg, she gets him to a cabin and sets the leg in splints. King has Buck sniff the scarf that Cassidy gave him and sends the dog to find Cassidy. When Jennings and Donaldson come across Buck, Jennings fires at him and misses. They then follow Buck's tracks hoping to find Jean. After King tells Jean about the murder, Jean surmises that Wolf must have killed the watchman. Worried about her father, King urges her to warn him, but just then, they hear Jennings and Donaldson approach. When Jennings enters, Jean gets his gun. As King then shoots Donaldson, Wolf attacks King, and Jennings retrieves his gun from Jean. Buck, whose mate had earlier been killed by Wolf, jumps in the window, and Wolf releases King to fight him. Cassidy, who has followed Buck back, shoots Jennings after he fires first. Buck chases Wolf into the wilderness, while Cassidy reports that Alison is alright and admits that he was wrong about duty and women never mixing.