When cowboy Lefty Brown witnesses the murder of his longtime partner, the newly-elected Senator Edward Johnson. He strikes out to find the killers and avenge his friend's gruesome death. Tracking the outlaws across the vast and desolate Montana plains, Lefty recruits a young gunslinger, Jeremiah, and an old friend, a hard-drinking U.S. Marshall, to help deliver the men to justice. After a gunfight with the outlaws leaves Jeremiah wounded, Lefty returns home with the names of Johnson's killers only to find that he is being accused of his friend's murder. With the tables turned, and with his friend in the governor's mansion refusing to help, Lefty must evade the law and prove his innocence by exposing the powerful men ultimately responsible for Johnson's death.