The adventurous story is set in the late 1750s during the French and Indian wars at Lake Ontario. Together with the Ranger Natty Bumppo, the officer Cap tries to reach Fort Oswego with his niece. They have to pass through an area controlled by enemies. By a betrayal they come into an almost hopeless situation and must fight for their lives.
The novel is the fourth volume of the five-part Leatherstocking Tales.