Elizabeth thinks she knows the gloomy Fenlen Forest.But when her treasured unicorn fawn, Sida, goesmissing, Elizabeth tracks her into a strange land wherethe people think Elizabeth is a changeling, a malignant beingwho too closely resembles a missing girl. If Elizabeth can find her fawn and uncover the fate of herlost double, can she stop the fear from turning into hate?To solve the deepening mystery, Elizabeth befriends ahandsome, skeptical young shepherd whose stories hint ata dark secret lurking at the forests edge, and follows a herdof wild unicorns with the ability to unlock the past.