In 1867 Scotland, sixteen-year-old Iris Finlay’s world shatters when her grief-stricken father abandons his ministry and departs for Ecuador on a plant-hunting expedition. Sent to live with her aunt at Drummond Castle, Iris finds solace in Innerpeffray Library and an unexpected friendship with talented artist Annie Cooper. She hatches a plan for independence through their joint botany publication. When the charming Spanish botanist Rafael de Rias enters their lives before mysteriously joining her father abroad, both girls are enthralled, then dashed. Iris is inspired and also faces disgrace working as rebellious Princess Louise’s chaperone in Balmoral. But after receiving devastating news, Iris uncovers the secret tale of a rare black orchid. Enlisting help from Annie’s brother Struan, can she piece together a botanical mystery?