After fighting the Confederacy during the Civil War, Lt. John J. Dunbar is rewarded for his bravery. He requests to be sent to the frontier. Lt. Dunbar, (Kevin Costner) arrives at the deserted Ft. Sedgwick. The post is rundown, but he decides to stay and rebuild along with discovering his new surroundings. He encounters the Sioux Indians, his new neighbors. They try to intimidate him, but he is more curious about the people trying to make him leave. He documents each experience in his journal. He decides to go find the Sioux camp. Upon approaching the camp, comes upon a Sioux woman, Stands With a Fist. She is mourning the death of her husband, and is frightened to see him. He convinces her that he is not going to hurt her, and takes her back to the camp for help.
He establishes his presence with the medicine man Kicking Bird and Wind in His Hair. He continues to go to the camp to learn of their customs. Stands With a Fist helps him because she is really a white woman who was adopted by the medicine man when her family was killed by another Indian tribe. They eventually marry. While at the fort, he would see a wolf at night. The Sioux observed him dancing around the campfire, thus, they named Dunbar Dances With Wolves. Gradually, he sheds his army uniform for the native garb of the Sioux. After a time away from the fort, he leaves the Sioux camp reassuring them he will return. Upon his arrival, there is a regiment at the post. Not being in uniform, they mistake him for an Indian, beat and lock him up. After reading his journal the sergeant discovers who he is and accuses him of deserting. The Sioux are worried and don't want to leave camp without him, so they come to help him escape. Knowing that the Army will come for him, the tribe moves on, and he and Stands With a Fist go in another direction.