Twelve-year-old orphan Roo Fanshaw is sent to live with an uncle she never knew in a largely uninhabited mansion on Cough Rock Island and discovers a wild river boy, an invalid cousin, and the mysteries of a hidden garden.

It is World War II, and Franny and her parents, Sina and Old Tom, enjoy a quiet life on a farm on Vancouver Island. Franny writes, Sina sculpts, and Old Tom tends to their many gardens--including the ancient, mysterious night garden. Their peaceful life is interrupted when their neighbor begs Sina to watch her children. Soon after the children move in, amid the chaos of the household, Sina sees UFOs, a hermit makes himself useful, a mystery involving...