1911. In a forgotten valley on the Devon-Somerset border, the seasons unfold, marked only by the rituals of the farming calendar. Twelve-year-old Leopold Sercombe skips school to help his father, a carter. Skinny and pale, Leo dreams of a job on the estate's stud farm. He is breaking a colt for his father when a boy dressed in a Homburg, breeches and riding boots appears. Peering under the stranger's hat, he discovers Miss Charlotte, the Master's daughter. And so begins a friendship between the children, bound by a deep love of horses, but divided by rigid social boundaries – boundaries that become increasingly difficult to navigate as they approach adolescence.