By 1755, fighting between England and France spills over into the New World and begins to affect the colonies. At the British headquarters in Albany, New York, near the southern edge of the ancient Indian war path known as the Iroquois Trail, Capt. Jonathan West delivers a dispatch to Col. Eric Thorne, the father of his onetime sweetheart Marion. Thorne summons all officers to Gen. Johnson's office, where they learn that French Gen. Montcalm's troops and his allies, the Huron Indians, have assembled at the border and threaten to attack their garrison at Crown Point. Thorne orders Sgt. Tom Cutler to deliver a dispatch to warn Crown Point of the impending attack and tells trail scout Sam Girty and his guide Ogane, a Huron chieftain impersonating a friendly Delaware Indian, to lead him to his mother's cabin, where he will be able to pick up the trail. They arrive, and when Tom says farewell and turns to enter the cabin, Girty shoots him in the back and steals the dispatch from his saddle bag. At that moment, Ma Cutler's other son Nat, whose scouting abilities have earned him the nickname "Hawkeye," arrives at the cabin with his Delaware Indian guide, Sagamore. Girty, meanwhile, tells Ogane to scalp Tom so that the Army will suspect that Indians killed him, but before he can do so, they see Nat running toward them firing his gun. After they escape, Girty instructs Ogane to deliver the dispatch to Montcalm, then lies to Lt. Blakeley, saying that Tom willingly gave the dispatch to a Huron. Meanwhile, at her cabin, Ma nurses Tom, who is drifting in and out of consciousness. Sometime later, Nat finds Girty at a tavern and shoots him, but he escapes on a horse. Later, Gen. Johnson receives word that an unsupported Crown Point has been attacked and assigns Jonathan to Fort Williams, near the Crown Point. Johnson then tells Marion, Jonathan and Sagamore to follow Ogane to Fort Williams, where they will arrive a couple of days ahead of the battalion. Nat and Sagamore are given permission to accompany them and help the party escape unharmed after they are attacked by Ogane's braves. Shortly after they arrive at the fort, Montcalm's forces attack, and a five-day siege ensues. When the fort runs short of gunpowder, Blakeley decides to send Ogane for reinforcements. Ogane leaves to meet secretly with Capt. Brownell, a French soldier spying in the British ranks, and Nat and Sagamore follow. Not realizing that Brownell is also a spy, Nat bursts in and exposes Ogane as a traitor. Brownell tries to draw his gun, but Nat does so first and shoots him, after which Nat and Sagamore are locked in the fort's jail. Ogane's braves break into the fort, kidnap Marion and take her back to the Huron village, where Ogane plans to marry her. Before the ceremony is performed, Marion is rescued by Nat and Sagamore. While they are escaping, however, Sagamore is killed when a Huron throws a tomahawk into his back. Sometime later at headquarters, Jonathan celebrates his new assignment as battalion commander, while Nat eagerly accepts his assignment as a battalion scout.