Canadian Mounties Corporal Rod Webb and Constable Mike Kelly, along with Rod's dog Chinook, are sent to the Blackfoot Crossing country to find the killer of trapper Antonie Dubois, and also to investigate reports of illegal deals in beaver pelts. Mike, a rookie, is delighted with the assignment as it takes him to his home country where he again sees Sandra Dubois, his childhood sweetheart. Posing as trappers, Rod and Mike meet Matt Oliver, introduced as a mining engineer, at Sandra's home, who is a little irked at the warm welcome Mike receives from Sandra. The undercover Mounties soon get on the trail of Morgan, Howell and Cheval, the illegal beaver trappers. While searching for evidence in the trading post ran by MacGregor, Mike is surprised by Morgan and Cheval and is killed. Rod closes the trail that reveals Oliver as the leader of the gang. Chinook takes care of Oliver, and Rod arrests Morgan and the others.