1912: Twenty-one-year-old Tilly Harper leaves the peace and beauty of her native Lake District for London to become assistant housemother at one of Mr. Shaw's Training Homes for Watercress and Flower Girls. For years, the homes have cared for London's orphaned and crippled flower girls, getting them off the streets. For Tilly, the appointment is a fresh start, a chance to leave her troubled past behind. Soon after she arrives at the home, Tilly finds a notebook belonging to Flora Flynn, who sold flowers with her sister Rosie decades before. Flora's entries reveal a heartbreaking tale of loss and separation, one that sends Tilly on a mission to discover what happened to Rosie.