1885-1914. Mary Fields, a fifty-three-year old second-generation slave, emancipated and residing in Toledo, receives news of her friend's impending death. Remedies packed in her satchel, Mary rushes to board the Northern Pacific. Days later, she arrives in the Montana wilderness to find Mother Mary Amadeus lying on frozen earth in a broken-down cabin. Certain that the cloister of frostbit Ursuline nuns and their students, Indian girls rescued from nearby reservations, will not survive without assistance, Mary decides to stay. She builds a hennery, makes repairs to living quarters, cares for stock, and treks into the mountains to provide food. Brushes with death do not deter her. Mary drives a horse and wagon through perilous terrain and sub zero blizzards to improve the lives of missionaries, homesteaders and Indians and, in the process, her own.