WYOMING, 1861 AND THE PONY EXPRESS TRAIL IS FULL OF PERIL . .
When her father dies suddenly, 15-year-old Lexie McDonald is left an orphan. Her brother, Callum, is on the run, accused of a crime that he didn't commit, and plans are in place to send Lexie to live with an aunt in New York City. Rather than be separated from her beloved horse, Cougar, Lexie makes the bravest decision of her life. Disguised as a boy, she sets out with Cougar along the dangerous Pony Express trail to find Callum and clear his name.