A novel about a lost girl and her horse, the enduring strength of friendship, and how even the smallest choices can change everything. When Sarah's grandfather gives her a beautiful horse named Boo-- hoping that one day she'll follow in his footsteps to join an elite French riding school, away from their gritty London neighborhood-- she quietly trains in city's parks and alleys. But then her grandfather falls ill, and Sarah must juggle horsemanship with school and hospital visits. Natasha, a young lawyer, is reeling after her failed marriage: her professional judgment is being questioned, her new boyfriend is a let-down, and she's forced to share her house with her charismatic ex-husband. Yet when the willful fourteen-year-old Sarah lands in her path, Natasha decides to take the girl under her wing. But Sarah is keeping a secret-- a secret that will change the lives of everyone involved forever.