Princess Tania thinks she has finally found a way to unite the world of Faerie with the modern world, but her beloved Immortal Realm is threatened when a grave illness takes hold of the kingdom and she must find a way to save it.

Sixteen-year-old Rue Silver, whose mother disappeared weeks ago, believes she is going crazy until she learns that the strange things she has been seeing are real, and that she is one of the faerie creatures, or Good Neighbors, that mortals cannot see.

After nine years Clare Macleod and her father are finally returning to their old home in Ireland, a house by the sea, with a yew tree growing inside it, a tree with its roots in both the human and fairy world--and soon Clare, who has always been able to sense the "Strange," meets the boy Finn, and discovers that she must battle against the forces of evil to restore order to both worlds.