Alice Wright has travelled halfway across the world to escape her stifling life in England. Handsome American businessman Bennett Van Cleve represents a fresh start. But she soon realises that swapping the twitching curtains of suburbia for newlywed life in the wild mountains of Kentucky isn't the answer to her prayers. But maybe meeting Margery O'Hare is. The heart and backbone of the small community of Salt Lick, a woman who isn't afraid of anything or anyone, Margery is on a mission.

Enlisting Alice, along with three other women, all from very different backgrounds, to join her, the band of unlikely sisters battle the elements and unforgiving terrain - as well as brave all manner of dangers and social disapproval - to ride hundreds of miles a week to deliver books to isolated families. Transforming the lives of so many is all the impetus they need to take such risks.

And for Alice, her new job and blossoming friendships become an unexpected lifeline, providing her with the courage she needs to make some tough decisions about her marriage. Then a body is found in the mountains, rocking the close-knit community and tearing the women apart as one of them becomes the prime suspect. Can they pull together to overcome their greatest challenge yet?

Inspired by a remarkable true story, the unforgettable journey of five extraordinary women living in extraordinary and perilous times.