Ever Since Lacey and Cal's adventure through the Neitherswarth, the two stepsisters have never been closer. But when Cal comes to visit Lacey at St. Agatha's Boarding School for Girls, Lacey can't help but feel nervous. She wants to embrace her new family, but would doing so betray her late mother's memory?

Cal convinces Lacey to explore Warble Hall, a long-abandoned dorm on St. Aggie's campus, before it's torn down. Little do they suspect that the spirits of the building's former residents still roam the halls, ruled over by an evil housemother who's determined to make Lacey and Cal her newest wards.

With the help of a spirited new friend-who just might have a surprising connection to Lacey's past-the Berge sisters will have to avoid the housemother's clutches, outsmart a mad wraith, and face down a clique of ghostly mean girls, all before the building is demolished at dawn.

Can Lacey and Cal escape, or will they become permanent residents of Warble Hall?