It's 1887, and Annie and Buffalo Bill's Wild West Show are invited to Queen Victoria's Jubilee celebration in London, England. But their long journey across the Atlantic takes a turn for the worst when the queen's royal servant ends up dead and Annie's husband, Frank Butler, falls suspiciously ill. Annie soon discovers that the two events are connected—and may possibly be precursors to an assassination attempt on the queen. In London, it becomes clear there is rampant unrest in the queen's kingdom—the Irish Fenian Brotherhood, as well as embittered English subjects, are teeming in the streets. But amid the chaos, even while she prepares for the show, Annie is determined to find the truth. With the help of a friend and reporter, Emma Wilson, the renowned poet Oscar Wilde, and the famous socialite Lillie Langtry, Annie sets out to hunt down the queen's enemies—and find out why they want to kill England's most beloved monarch.

Fifteen-year-old Annie Oakley is the sole supporter of her widowed mother and two siblings. An expert markswoman and independent spirit, she hunts game to sell to the local mercantile to make ends meet instead of accepting a marriage proposal that could solve all her problems. After a stunning performance in a shooting contest against the handsome and famous sharpshooter Frank Butler, Annie is offered a position in the renowned Buffalo Bill's Wild West Show. Finally, she has a chance to save the nearly foreclosed family farm and make her dreams come true. But then her Indian assistant is found dead in her tent, and Annie is dubious when the local coroner claims the death was due to natural causes. When another innocent is murdered, Annie begins to fear the deaths are related to her. And to make matters worse, her prized horse, Buck, a major part of her act, is stolen. Annie soon discovers that the solution to her problems lies buried in a padlocked Civil War trunk belonging to the...