The Prairie, published in 1827, was the last in the series of books known as The Leatherstocking Tales written by James Fenimore Cooper. The story opens with a wagon train headed west in 1805. They are deep within the territory known as the Louisiana Purchase and are intending to make their new homes on the prairie lands of the west. Ishamel and Ether Bush, Abiram White (Esther's brother), Ellen Wade (the Bush's neice), Dr. Obed Bat, an eccentric naturalist and the large Bush family that includes several grown sons make up this party of would-be settlers.
As they search for a suitable location for their camp for the night, they see the profile of Natty Bumbo outlined against the horizon. At first they think he is an illusion, but the truth is that Natty is just as surprised to see them as they are to see him. Once a great trapper and scout in the earlier Leatherstocking Tales, Natty has aged and now resorts to trapping small game for a living. He is amazed to see a group of white people this far from civilization. He leads them to a suitable campsite and helps them set everything up for the night.
Natty notices that one of the wagons is being kept away from the others and is guarded. When he approaches to determine the reason for this Abiram White roughly pushes him away. He has supper with the settlers and answers there many questions about what they can expect on the trail. He leaves the camp for his own campsite and is surprised to see Ellen Wade walking alone. It is then that he finds her boyfriend Paul Hover has followed the wagon train and that Ellen was the only one that knew of him being in the area. While the three are talking, they are attacked by a party of Sioux Indians and taken captive.
The Sioux chief then silently makes his way into the camp of the white settlers and sets the animals free. After this the band sets up a major racket to frighten the animals and send them scampering over the prairie. Natty relies on his store of knowledge and waits for a chance for the Indians to let down their guard. He gets free and lets the Sioux horses free. He and Ellen return to the wagon train and Paul returns to his own hiding place.
Dr. Bat had been absent from the camp when the Sioux released all the animals. He returned the next morning to inform his companions of his discovery of strange animal in the area only to find that it was his own donkey that the Indians had set free. With no animals, the wagon train is now stranded. Natty leads them to a hilly area where they can take a stand against the Sioux and Bush's strong sons haul the wagon to this location. Again Natty's curiosity is aroused by the protected wagon and again he faces the hostility of Abiram White.
It is discovered that the occupant of the wagon to be a woman unknown to the others. This heads Asa, the eldest Bush son to accuse his uncle of having kidnapped her and this leads to a war of words in which the reader discovers that the Bush family is wanted by the authorities in Kentucky.
At the same time, in Paul's hideout, Natty, Paul and Dr. Bat feast on buffalo meat. While the three are talking, Natty hears a noise in the bush that he knows does not pose any danger to them. They are surprised though to see Captain Duncan Uncas Middleton emerge. He is the grandson of the main characters from the novel The Last of the Mohicans and is hunting for his wife – the lady in the wagon.
Back at camp, Ellen has been left to guard the wagons and to look after the children. The four men arrive and realize who is being held in the wagon. They attack the wagon train and Ellen is forced to defend the camp against them. Inez, the Captain's wife emerges and begs them to stop the fighting. She and her husband are reunited and Ellen rushes to help her leaving her post allowing the men to enter.
Inez had been kidnapped by Abirma shortly after her marriage. Middleton was pursing them with a band of soldiers She leaves the camp with Natty, her husband, Paul and Dr. Bat. Ellen decides to follow Paul and goes with them. They travel across the prairie meeting up with the chief of the Pawnee tribe, Hard-Heart, and from here on in the novel, the Sioux are seen as the bad Indians and the Pawnees as the good Indians. Hard-Heart promises the group refuge in his camp. It is far from where they are now, but so is the place where Middleton is supposed to meet up with his soldiers.
A stampeding herd of buffalo threatens to kill the group, but Natty's skill comes into play as he manages to split the herd leading them away from the people. A Sioux hunting party had been the cause of the stampeded and Natty hopes to trick them into thinking he is alone to give the others time to escape. However, they do reveal themselves to the Indians preferring captivity to being discovered by the Bush family.
When the Sioux see the Bush family on foot and away from the camp, they decide to attack. As they do so, Natty and the two couples are able to escape on horses belonging to the Indians. Dr. Bat had been allowed to leave earlier because the Indians feared him as a medicine man and the five others soon catch up with him. When the Sioux realized their captives had escaped, they set fire to the grass on the prairie. Natty starts a backfire, once again saving the lives of the five people with him.
They meet up with Hard-Heart who tells them that the Sioux and the Bush family have become friends and have joined forces in searching for them. However, all of them are captured by the Sioux and Ishmael Bush demands his wagons and the white prisoners be returned to him. The Sioux only returned the wagons, though, and Hard-Heart is led to the stake to be tortured. Natty promises he will go to the Pawnee camp to inform them of his death and to bring back a calf so that the chief may have food in the afterlife.
The torture does not take place as planned because the Sioux chief wants Inez and Ellen to remain in his tribe. One of the younger wives pleads him not to keep the strangers and this episode delays the torture. Then an older chief claims Hard-Heart as his son and them when a Sioux warrior tries to attack Hard-Heart with a tomahawk, he is able to escape into a river. Just then the Pawnee horsemen arrive.
The older women of the tribe are ordered to kill the white prisoners, but they have managed to cut their bindings. While they are not yet ready to fight, they are saved temporarily by the arrival of Bush and his sons, who do capture them and carry them back to their camp. While this was taking place a battle raged between the Pawnee and the Sioux. Although the Sioux leader is killed, they are winning until Ishmael turns on them and starts shooting. A massacre ensues and only a few of the Sioux escape.
The following day, Ishmael sets himself up as judge and jury releasing the Middletons and Ellen and Paul. He also releases Hard-Heart and Dr. Bat, but keeps Natty prisoner. A fight breaks out between Asa and Abiram, in which Abiram shoots Asa in the back. His sister wants him to die for this crime and he is placed on a narrow ledge of a cliff with his arms bound. His hands are left free to read a Bible. Ishmael leaves him here and continues on his journey. Natty is released as a result.
The six white freed prisoners return to the Pawnee village but Natty asks to be put ashore on a riverbank before they reach the main camp when they decide to go back to civilization. He is unable to live among white people again having lived so long on his own. He returns to live with the Pawnee.
The following year, Captain Middleton makes the journey back to reunite with Natty only to find that he was dead. He arrives on the day of the funeral at which the whole tribe had turned out to pay their respects. Natty became a legend among the Plains Indians and a memorial to him was erected by Middleton.