Major Duncan Heyward has been ordered to escort Cora and Alice Munro from Fort Edward to Fort William Henry, where the young women’s father, Colonel Munro, is commandant. Also in the party is David Gamut, a Connecticut singing master. On their way to Fort William Henry, they do not follow the military road through the wilderness. Instead, they place themselves in the hands of a renegade Huron known as Magua, who claims that he can lead them to their destination by a shorter trail.
It is afternoon when the little party meets the woodsman Hawkeye and his Delaware Mohican friends Chingachgook and his son Uncas. To their dismay, they learn that they are but an hour’s distance from their starting point. Hawkeye deduces that Magua has been planning to lead the party into a trap. His Mohican comrades try to capture the renegade, but Magua flees into the woods. At Heyward’s urging, Hawkeye agrees to guide the travelers to their destination. After the horses are tied and hidden among rocks along a river, Hawkeye produces a hidden canoe from among the bushes and paddles the party to a rock at the foot of Glenn’s Falls. There they prepare to spend the night in a cave.
That night, the party is surprised by a band of Iroquois led by Magua. Hawkeye, Heyward, and the rest might have a chance of victory, but unfortunately their ammunition, which was left in the canoe, has been stolen by one of the enemy. Their only hope then lies in the possibility of future rescue, for the capture of the little group is a certainty. Hawkeye, Chingachgook, and Uncas escape by floating downstream, leaving the Munro sisters and Major Heyward to meet the savages.
Captured, Cora and Alice are allowed to ride their horses, but their captors force Heyward and David to walk. Although they take a road paralleling the one that leads to Fort William Henry, Heyward cannot determine the destination the Indians have in mind. Drawing close to Magua, he tries to persuade him to betray his companions and deliver the party safely to Colonel Munro. The Huron agrees on the condition that Cora be given to him to live with him among his tribe as his wife. When she refuses, the enraged Magua has everyone bound. He is threatening Alice with his tomahawk when Hawkeye and his friends creep up silently on the band and attack. The Iroquois flee, leaving several of their dead behind. The party, under David’s guidance, sings a hymn of thanksgiving and then pushes onward.
Toward evening, they stop at a deserted blockhouse to rest. Many years before, it had been the scene of a fight between the Mohicans and the Mohawks, and a mound still shows where bodies lay buried. While Chingachgook keeps watch, the others sleep, and then at moonrise they continue on their way. It is dawn when Hawkeye and his charges draw near Fort William Henry. They are intercepted and challenged by a sentinel of the French under Montcalm, who is about to lay siege to the fort. Heyward is able to answer him in French, and they are allowed to proceed. Chingachgook kills and scalps the French sentinel. Then, through the fog that has risen from Lake George and through the enemy forces that throng the plain before the fort, Hawkeye leads the way to the gates of the fort.
On the fifth day of the siege, Hawkeye, who has been sent to Fort Edward to seek help, is intercepted on his way back, and a letter he carries is captured. Webb, the commander of Fort Edward, has refused to come to Munro’s aid. Under a flag of truce, Montcalm and Munro hold a parley. Montcalm shows Webb’s letter to Munro and offers honorable terms of surrender. Colonel Munro and his men will be allowed to keep their colors, their arms, and their baggage if they vacate the fort the next morning. Helpless to do otherwise, Munro accepts these terms. During one of the parleys between the English and the French, Heyward is surprised to see Magua in the camp of the French. He was not killed during their earlier skirmish.
The following day, the vanquished English leave Fort William Henry and start for Fort Edward. Under the eyes of the French and their Indian allies, they pass across the plain and enter the forest. Suddenly an Indian grabs at a brightly colored shawl worn by one of the women from the fort. Terrified, she pulls the shawl closer and wraps her baby in it. The Indian darts to her, grabs the infant from her arms, and dashes the child’s head against a rock. Then, under the eyes of Montcalm, who does nothing to hold back his savage allies, a monstrous slaughter begins. Cora and Alice, entrusted to David Gamut’s protection, are in the midst of the killing when Magua swoops down upon them and carries Alice away. Cora runs after her sister, and faithful David follows her. They are soon atop a hill, from which they watch the slaughter of the garrison.
Three days later, Hawkeye, leading Heyward, Munro, and his Indian comrades, tracks the young women and David with the help of Cora’s veil, which had caught on a tree. Heyward is concerned above all for the safety of Alice. The day before the massacre, he had been given her father’s permission to court her.
Hawkeye, knowing that hostile Indians are on their trail, decides that they should save time by traveling across the lake in a canoe that he has discovered in its hiding place nearby. He is certain that Magua has taken the Munro sisters north, where he plans to rejoin his own people. Heading their canoe in that direction, the five men paddle all day, at one point having a close escape from some of their enemies. They spend that night in the woods, and the next day they turn west in an effort to find Magua’s trail.
After much searching, Uncas finds the trail of the captives. That evening, as Hawkeye and his party draw near the Huron camp, they meet David Gamut wandering about. He tells his friends that the Indians think him crazy because of his habit of breaking into song, and they allow him to roam the woods unguarded. Alice, he says, is being held at the Huron camp, and Cora has been entrusted to the care of a tribe of peaceful Delawares a short distance away.
Heyward, disguising his face with paint, goes to the Huron camp in an attempt to rescue Alice while the others set about to help Cora. Heyward has been in the camp but a short time, posing as a French doctor, when Uncas is brought in, a captive. Called to treat a sick Indian woman, Heyward finds Alice in the cave with his patient. He is able to rescue her by wrapping her in a blanket and declaring to the Hurons that she is his patient, whom he is carrying off to the woods for treatment. Hawkeye, attempting to rescue Uncas, enters the camp disguised in a medicine man’s bearskin he has stolen. He cuts Uncas loose and gives him the disguise, and the woodsman borrows David Gamut’s clothes. The singer is left to take Uncas’s place while the others escape, for Hawkeye is certain that the Indians will not harm David because of his supposed mental condition. Uncas and Hawkeye flee to the Delaware camp.
The following day, Magua and a group of his warriors visit the Delawares in search of the escaped prisoners. The chief of the Delawares decides that the Hurons have a just claim to Cora because Magua wishes to make her his wife. Under inviolable Indian custom, the Huron is permitted to leave the camp unmolested, but Uncas warns him that in a few hours he and the Delawares will follow his trail.
During a bloody battle, Magua flees with Cora to the top of a cliff. There, pursued by Uncas, Magua stabs and kills the young Mohican; he is then, in turn, sent to his death by a bullet from Hawkeye’s long rifle. Cora, too, is killed by a Huron. Amid deep mourning by the Delawares, she and Uncas are laid in their graves in the forest. Colonel Munro and Heyward conduct Alice to English territory and safety. Hawkeye returns to the forest. He has promised to remain with his sorrowing friend Chingachgook forever.