In 1880 in Yell County, Arkansas, 14-year-old Mattie
Ross vows vengeance on her father's murderer, hired man Tom Chaney,
who has fled into Indian Territory. Accordingly, she enlists
the aid of one-eyed U. S. Marshal Rooster Cogburn and accepts the
help of Texas Ranger La Boeuf, who is intent on the reward awaiting
the man to capture Chaney for crimes committed in Texas.
Despite mutual distrust, Rooster and La Boeuf unite
to dissuade Mattie from accompanying them on their dangerous
mission. Undeterred, she joins the manhunt. The trio
tracks the assassin across the border to the refuge of outlaw Ned
Pepper. During a surprise raid on Pepper's hideout, the lawmen
kill four of his fellows and find a gold piece once the property of
Mattie's father. Alone, Mattie encounters Chaney.
Although she wounds him, Mattie is taken hostage by Pepper's band.
Fearing for the girl's life, La Boeuf and Rooster pretend to
retreat.
Armed to the teeth, the two return unexpectedly to
rescue Mattie. As Chaney bludgeons La Boeuf, Mattie shoots the
fugitive a second time and falls backwards into a snake pit.
After slaying Chaney, Rooster, aided by the dying ranger, pulls
Mattie from the pit. Discovering that she has been bitten by a
rattlesnake, the marshal, himself wounded, rushes the girl to a
physician. Recovering from her injuries, the child proclaims
to Rooster her wish to be buried next to him.