Fresh off a failed Nebraska farm, seventeen-year-old William J. Buckmeister is looking for adventure and enlists in the fabled U.S. 7th Cavalry just prior to General Custer's ill-fated campaign of 1876. He is issued the standard Colt 1873 Single Action Army revolver, a firearm he will carry with him throughout his life, and one that will soon define him. Through long hours of practice, "Buck" masters the art of the fast draw. After an injury forces him out of the army, he tumbles headlong into the rough and dangerous outlaw world. Shooting and killing his way across the untamed western territories, he soon establishes a reputation as one of the deadliest "shootists" of the Old West. As the twentieth century approaches, Buck struggles to adjust to modernity but finds himself drawn deeper into a life marked by criminal activity, violence, and chronic depression. Even the love of his wife Maggie, a suffragette and political activist, cannot calm the turmoil that rages within him. Forced out of Prohibition-era Chicago, Buck returns to the Windy City in the sunset of his long life, only to find that his phenomenal skills with the Army Colt will be called upon in a final, bloody confrontation-one that may be his last chance for redemption.