Major Rogers plans for a decisive blow against the French army are thwarted when Ensign Towne is captured by Black Wolf's tribesmen. Rogers must rescue his young officer before the Indians can force him to reveal the Rangers attack plans.
Maj. Rogers, Sgt. Marriner and Ens. Towne are captured by a French patrol and thrown into a prison stockade. There they are subject to inhuman conditions and brutal torture by the sadistic French commander, Maj. Marten.
A bounty hunter reports that the Mohegans, an Indian tribe who were previously neutral in the fight between the French and the English colonists, are preparing to go on the warpath against the Anglo-Americans. Rogers distrusts the man's story and over the bounty hunter's objections is determined to investigate first, rather than make a preemptive strike against a previously peaceful tribe.
Sir Martin Stanley is determined to avenge himself upon Major Rogers and his men because his wife flirted with the Ranger commander when last they met. He blocks all attempts to appropriate funds to pay his troops and then schemes to have Rogers and his two right hand men, Hunk Marriner and Langton Towne shanghaied aboard a sailing ship bound for the far reaches of the British empire.
Maj. Rogers, Sgt. Marriner and Ens. Towne dine at a local tavern, and when they go to pay the bill, they find that their money--which they've just received from the military paymaster--is counterfeit. An investigation reveals that counterfeiting isn't the only criminal activity going on.
The French capture a British spy upon Quebec's Plains of Abraham and are convinced that he has discovered a route to climb the 200 foot cliffs that protect the city from the St. Lawrence River below. The British army believes this two and sends Rogers with a beautiful double-agent to Quebec to try to learn about the route from the spy who is imprisoned in the city's deepest dungeon.
Two escaped convicts break into a trapper's cabin. While the man is sleeping, they eat his food, steal his pelts and a rifle and leave. What they don't know, however, is that the trapper wasn't sleeping--he was dying of smallpox. When the Rangees discover what has happened, they set out to capture the fleeing men before they're able to get to Portsmouth and bring that contagious, and fatal, disease with them.
When a local trapper is robbed and murdered, suspicion immediately falls on a family of troublemakers, the Wade brothers. However, Dan Wade, the youngest brother, insists that he had nothing to do with the crime and pleads with Maj. Rogers to help prove his innocence.
While scouting French army positions, Rogers is shot. He manages to elude his pursuers and floats downstream unconscious until his canoe is recovered by an old woman skilled in herbs and poultices who recently escaped from Indian captivity. The woman is accused of witchcraft by a sick child and when a traitor learns she was caring for the injured Rogers, plans to turn the ranger over to the French for the thousand dollar reward.
Rogers must learn why his men are being killed and stripped of their uniforms before an envoy with important dispatches reaches the Crown Point area. He suspects that a new trading post owner and his beautiful daughter are involved and details Ensign Towne to learn more about the recent arrivals, much to the young man's delight.