Mattie Ross, a determined 14-year-old from Yell County, Arkansas, sets out on a mission of vengeance after the shocking murder of her father, Frank Ross. He fell victim to his hired hand, Tom Cheney, who, in a drunken rage after a card game, not only killed Frank but also made off with his horse. Fueled by grief and resolve, Mattie decides to take matters into her own hands to seek justice.
Traveling to Fort Smith, the location of her father's death, Mattie identifies his body and showcases her fearless negotiating skills by buying back her father's ponies for $320 from a reluctant seller. She then resolves to hire a U.S. Marshal to track down Cheney. After consulting the local sheriff, she learns of the notorious Rueben “Rooster” Cogburn. Determined, Mattie finds Cogburn at a saloon, but he dismissively rebuffs her attempts to hire him. After confrontations at a court hearing and another failed appeal, she’s left feeling the urgency of her quest.
Things take an interesting turn when a Texas Ranger, LaBouef, arrives at the boarding house where she’s staying. He's been pursuing Cheney for months, having tied him to the murder of a Texas senator. LaBouef proposes a partnership with Cogburn to track Cheney down, but Mattie, adamant and independent, declines. The next day, she reclaims her father's pony, which she names Little Blackie, signaling her readiness for the journey.
When Mattie approaches Cogburn, he initially agrees but soon abandons her. Undaunted, she tracks him to a river and swims across to join him. Impressed by Mattie's determination, outside of his usual camaraderie with LaBouef, Cogburn begrudgingly continues the journey alongside her. Their path brings them face to face with Cheney and his gang, led by the notorious Lucky Ned Pepper.
While seeking refuge in a cabin, tension escalates when Cogburn makes a desperate deal with the injured gang member tied to the Pepper gang, ultimately resulting in violence. The adventure intensifies as they encounter LaBouef again and face the gang, leading to several unexpected turns, including the danger of death and betrayal.
The stakes rise dramatically when Mattie comes head-to-head with Cheney himself, and in a valiant showdown, she ultimately shoots him, completing her quest for revenge. However, this victory comes at a cost as she finds herself in a precarious situation after falling into a pit and getting bitten by a rattlesnake. Though Cogburn manages to rescue her, her injuries lead to complications that haunt her for years to come.
Years later, as an adult and reflecting on her tumultuous past, Mattie—now played by Elizabeth Marvel— recounts her harrowing adventures and regrets. Despite her resolute nature and refusal to marry, she feels the weight of time slipping away. Although she attempts to reconnect with Cogburn after writing to him, she learns of his death three days prior to her visit. With a heavy heart, she arranges for him to be laid to rest in her family's plot, contemplating the choices and events that defined her life, as she memorably states, “time just gets away from us.”
