The book begins in the middle of the French and Indian War in upper New York State near the Hudson River and Lake Chaplain.
General Webb has just gotten word from an Indian that Moncalm and the French are going to attack Fort William Henry and that Colonel Munro will not be ale to keep the fort because he only has one thousand men and that he (Webb) needs to send reinforcements immediately. Upon hearing this, he ordered fifteen hundred men to be ready to march at dawn and has Cora and Alice Munro sent to their father at Fort William Henry accompanied by Major Duncan Heyward on horseback. They went along an Indian path which was to get them to Fort William Henry faster and they were lead by an Indian runner, from the time they left Fort Edward the two sisters were suspicious of their Indian Guide, Le Renard Subtil.
A little while into their trip, they meet the singing master David Gamut who asked to accompany them to Fort William Henry. Not to far away in the same forest, were an Indian and a White man talking about their races existence in the “New World.” The Indian was Chingachgook, the chief of the Mohicans, and the White man, Hawkeye; this was the name given to him by the Indians. They talk for a while and then decide to eat. Uncas kills them something for dinner and shortly after, The Party on its way to Fort William Henry runs into them along the path. They stop for a while and talk and then ask for directions to Fort William Henry. Hawkeye is suspicious of their guide and ask to see him to find out if he is an Iroquois, Hawkeye looks and discovers he is.
Learning this, Duncan goes to keep their guide there so that Chingachgook and Uncas can do something about him. As Duncan was staling, Chingachgook and Uncas jumped out of the foliage and accidentally chased him away. They chase after him for a while and wound him but in the end, he is to fast for them and they return to Duncan and his party. Feeling that they were still not safe, Hawkeye offers to help them at no cost.
They boarded Hawkeyes canoe and they head for safety. Chingachgook and Uncas offered to lead the horses up stream to where the others were going by canoe. They go to and island at the foot of Glenns Falls for safety. Once everyone was one the island torches were lit and they went down into a cavern.
At the break of dawn, the Iroquois began their attack. The attack lasted all morning and then the Iroquois left to replenish their supplies. When the Iroquois leave Hawkeye sees they are out of powder for their guns and that they will all die when the Iroquois return.
At this point, Cora tells Uncas and Hawkeye, Chinachgook to swim down river and come back with rescue. About this time, they hear the shouts of the Iroquois and realize they havent yet been discovered. They immediately seek hiding in the cavern.
They are soon discovered and taken prisoner and taken away from the island. Their former guide now in charge of the attack against them says that he will release them if Cora will become his wife. When Cora refuses, the sisters and Heyward are tied to trees and are to die before sundown. Heyward cant stand this and gets free. Once free, he tackles their Le Renard. Heyward is soon pinned and is about to be killed when a rifle is fired and kills Le Renard.
This caused a battle to break out. Iroquois after Iroquois fell to the ground dead. The Iroquois are quickly defeated and Heyward and the sisters are reunited with Uncas, Hawkeye, and Chingachgook. Once reunited, they ride to an old blockhouse where they decide to rest. They rest here until the moon comes out, then they resume their journey the Fort William Henry.
By morning, they had reached the top of a mountain overlooking Fort William Henry. Form here, they plan how they will get to the fort. They see that the fog is moving in form the lake and that this is their opportunity to get to the fort unnoticed. While in the fog, they are discovered by the French and another battle breaks out. At the top of the fort is Colonel Munro, Alice cries out to him and he orders the gates to be opened. After five days and many losses for the English, Heyward met with Montcalm.
After this meeting Heyward returned to Munro with the message. A few hours later, Munro goes to meet with Montcalm bearing the white flag. Montclam offers to let the English go with their lives, weapons, and flags, if they surrender the fort at dawn of the next day, Munro agrees.
Everything is going fine and the English are being escorted out by the French until a greedy Indian tries to take a shawl from an English mother and he kills her for it, thus leading to another battle. During all this commotion, Magua grabbed Alice and ran off with her, David and Cora followed in pursuit. Because of the skirmish, Munro, Heyward, Uncas, Hawkeye, and Chingachgook, were not able to begin the search for Alice and Cora until hours after this had taken place. They soon find their trail and begin pursuit. They decide to spend the night back at the fort and go after them in the morning. When they woke up, they could see the faint smoke of a dying fire across the lake. Seeing this, they got in the canoe and headed toward it.
While heading toward the smoke, they were discovered by a group of Indians that chased them but were fought off. They reached the shore and soon found a track. They followed this track until they came to a place where it suddenly ended. Here they found their two horses that had been abandoned, this told them they were in Iroquois country and that an Iroquois village was not far off. After careful examination of the area, they managed to find Davids tracks, which they then followed. They hadnt been following these tracks for long when they came across David in Indian attire.
They found out the reason for this was that the Iroquois were so amazed by his singing that they dressed him as one of them and let him come and go at will, he then reveals where the sisters are being kept. Heyward decides to go back with Gamut and free Alice but first, he has Chingachgook disguise him as an Indian medicine man. Once inside the village, Heyward sees that Uncas has been taken prisoner. Heyward is asked if he will see a sick woman and he complies. As they travel to her they encounter a large bear. The bear follows them into the lodge where the sick and dying women was. When he was left to heal the woman, the bear stays and when everyone but Duncan and the sick woman are gone it stands up, pulls off its head to reveal Hawkeye.
Heyward finds out the Hawkeye had come to rescue Uncas. Hawkeye also told him that Alice was in another room. Hearing this, Heyward went to explain their plan to her. While he was doing this Magua came in and said that they were both to be killed. Just as he said this, the huge bear came up behind Magua and together Hawkeye and Duncan quickly bound and gagged him. They then wrapped Alice in blankets and Duncan took her out of the lodging. When he did this he told the sick womans friends that he had locked the evil spirit in the cave and that he was taking the woman to look for herbs for medicine for her in the forest.
When they reached safety, Hawkeye gave them directions to a friendly Delaware village he then went back to the Iroquois camp to rescue Uncas. He went to Davids lodge where together, they devised a plan. They got to where Uncas was and cut him free. Then he exchanged clothes with Hawkeye and putting himself into the bearsuit and then Hawkeye and David exchange clothes. Once this is done, they tie up David who is going to play the part of Uncas. Shortly after they reached the forest their trickery was discovered.
The Iroquois then went over to the Delaware village to see if they could peacefully retrieve their prisoner. The Delaware welcomes the Iroquois chief and the Iroquois lies to the Delaware so they bind Hawkeye. While this is happening, Cora goes and begs for mercy from Tamenund. When they try to put Uncas to death, they find a tattoo of a turtle on him and they bring him to Tamenund.
Uncas and Tamenund talk for a while and Tamenund finds out who he is. Having gained the upper hand, Uncas convinces Tamenund to let him, Hawkeye, and Cora free but Indian law cannot free Alice. Uncas tries to persuade The Iroquois chief to let Alice go but he refuses and rides off with her. Uncas makes a truce until the afternoon of the next day with the Iroquois and when that time came, they went to rescue Cora.
They find out that Cora has been hidden in a cave on the side of a mountain so thats where they go. The Iroquois chief and two of his braves try to fight off Hawkeye, Duncan, and Uncas. The chief uses Cora as a shield. The chief then pulled out a knife and asked Cora if she wanted to die or be his wife. She didnt answer so he killed her. Uncas froze in horror and the chief took this opportunity and killed him too.
The chief then ran up the mountain. Hawkeye stopped and aimed his rifle at the murderer. Having gotten a good deal above Hawkeye and Heyward now the chief pushed a large rock down towards them from above and then attempted to jump to a ledge where he could not be reached. As he jumped, he fell short of his target and just managed to grab hold of a bush growing from the side of the mountain.
Seeing this opportunity Hawkeye shot him and the chief fell to his death. There was a lot of mourning over Coras and Uncas death and there were funerals for both of them. For many years afterward, Hawkeye and Chingachgook prowled the forest together and never forgot the ties of brotherhood that had taken root on Uncas grave.