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 neighbour, Crying Alice, begs Sina to watch her children while she goes to visit her husband at the military base because she suspects he's up to no good. Soon after the children move in, letters arrive from their father that suggest he's about to do something to change their lives - and appearances from a stubborn young cook, UFOs, hermits, and ghosts only make life stranger. Can the forbidden night garden that supposedly grants everyone one wish help them all out of trouble? And if so, at what cost?