Imagine living in a mine 2,000 feet underground, in the damp and the dark, and filled with rats! Young Bethan is living a peaceful life in a coal mining town in South Wales. Her parents have sacrificed to send her to a private girls' school. But her world crumbles when her father is badly injured after a section of the mine collapses. Setting her dreams aside for the time being, Bethan must help support her family. Defying the laws forbidding it, she goes to work 2,000 feet underground in the dark, damp, and terrifying coal mine. Her only source of comfort comes in the form of Dobbin, the very pit pony who saved her father's life.