Setting out for a family day in Devon nine-year-old Keira Ball suffered catastrophic brain injuries in a car accident. Against all the odds her heart continued to beat. Halfway across the country the hospital in which Max Johnson lay with end-stage heart failure received a potentially life-saving call. In an act of extraordinary generosity Keira's parents and siblings immediately and unanimously agreed that she would have wanted her organs donated. Rachel Clarke relates the emotional and urgent journey of Keira's heart and meticulously unpicks the history of the remarkable surgery that made it possible: a testament to medical innovation that stretches back over a century involving the knowledge and dedication not just of headline-grabbing surgeons but of countless nurses and technicians immunologists and physicians of paramedics and the motorists who give way to their blue lights.