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.