Birdie Bagshaw has never known her parents. Having grown up in a children's home for mixed race children in 1950s Leeds, now she has come to live with her great-aunt Mabel in the Yorkshire Dales. From her arrival, things are strained, and Birdie cannot understand why she is treated like an outsider by the local children. When their bullying drives Birdie to hide in the nearby coal mine, she finds an unexpected rescuer in the form of Mr Duke, the last remaining pit pony in the village. As the weeks pass, Birdie forms a special bond with the spirited little pony. But his future is in danger, and Birdie comes up with a daring plan to save his life in return.