After the end of the Civil War frees her from slavery, Mary Fields secures a job as the groundskeeper of a convent in Ohio where she instantly forms a deep bond with the superior, Mother Amadeus Dunne. When Mother Amadeus Dunne heads to Montana to open up a school for Native American girls, she falls ill along the way, and Mary rushes to her side, with no intention of leaving until she’s fully recovered. Intrigued by the West, Mary soon discovers her free-spirited nature fits the frontier lifestyle, and stays, feeling at home in Montana. It doesn’t take long for Mary to make a name for herself and make history—becoming the first African American woman to carry mail for the U.S. Postal Service. Facing the unruly routes through the untamed West, Mary fearlessly takes on bandits and criminals, all to protect the contents in her satchel. Over time, she gains a reputation for her bravery and unwavering determination against the most dangerous outlaws, earning her the nickname “Stagecoach Mary.”