In 1757, British Army Major Duncan Heyward arrives in Albany, New York during the French and Indian War. He has been sent to serve Colonel Edmund Munro, who is the commander of Fort William Henry in the Adirondack Mountains. Heyward is tasked with escorting the colonel’s two daughters, Cora and Alice, to their father. Before they leave, Heyward asks Cora to marry him but she does not give him an answer.
An Iroquois named Magua is tasked with guiding Heyward, the two women, and a troop of British soldiers to the fort but instead he turns out to be a Huron who leads the party into a Huron ambush. Mohican chief Chingachgook, his son Uncas, and his white, adopted son, “Hawkeye”, kill the Hurons; only Magua escapes. The trio agree to take the women and Heyward to the fort. During the trek, attraction grows between Cora and Hawkeye as well as Uncas and Alice.
When the party reach the fort, they find it under siege by the French and their Huron allies. They sneak in and are greeted by Colonel Munro, who asks Heyward about his request for reinforcements. The major becomes jealous of the noticeable feelings developing between Cora and Hawkeye. He finally learns she will not marry him.
Munro refuses the militiamen’s request for permission to leave because the French and Indian allies are raiding homesteads along the colony’s borders. After Hawkeye helps them sneak away, he is arrested for sedition and sentenced to hang. However, without reinforcements, Munro is forced to seek a parley with the besieging general Louis-Joseph de Montcalm, who demands that the British abandon the fort. Munro, who is greatly outnumbered, has little choice but to accept the terms. But Magua is furious because the surrender has robbed him of his chance to kill Munro who once hurt him and his family.
Colonel Munro, leads his remaining soldiers, and civilians out of the fort. Away from the fort, Huron warriors begin a massacre of the column. Magua personally kills Munro by cutting out his heart. Hawkeye, Uncas, and Chingachgook fight their way out taking Cora, Alice, Heyward, and a few other stragglers with them. They take shelter behind a waterfall but the vengeful Magua eventually catches up with them, capturing Heyward and the women.
Magua takes his three prisoners to a Huron settlement. While he is addressing a sachem, Hawkeye interrupts him with a plea to save their lives. The paramount chief rules: Heyward should be returned to the British, Alice is given to Magua for the wrongs done to him by Munro, but Cora will be burned alive. Although Hawkeye is told he may go in peace for walking unarmed into a Huron village, he offers to take Cora’s place. Heyward, who was acting as the French translator, trades his life for Cora’s instead.
After Hawkeye and Cora have left the village, he mercifully shoots Heyward as he is being burned alive. Chingachgook, Uncas, and Hawkeye then chase after Magua’s party to rescue Alice. Uncas, who has raced ahead, falls from a cliff after being mortally wounded by Magua. Seeing his death, Alice falls to her own death despite Magua’s attempts to dissuade her. Eventually, Hawkeye and Chingachgook slay most of the remaining Hurons before Chingachgook personally kills Magua.
Hawkeye and Cora watch as Chingachgook prays to the Great Spirit to receive Uncas, proclaiming himself “the last of the Mohicans.”