In 1823, Hugh Glass guides Andrew Henry’s trappers through unorganized territory. While he and his half-Pawnee son, Hawk, are hunting, the company's camp is attacked by an Arikara war party. Glass recommends that the survivors travel on foot to Fort Kiowa, as traveling downriver will make them vulnerable. After docking, the crew stashes the pelts near the shore.
Glass is badly mauled by a grizzly bear and left close to death. Trapper John Fitzgerald, fearful of another Arikara attack, argues that the group must mercy-kill Glass and keep moving. Henry agrees, but is unable to pull the trigger; instead, he offers money for someone to stay with Glass. When the only volunteers are Hawk and the young Jim Bridger, Fitzgerald agrees to stay to recoup his losses from the abandoned pelts.