Key the Steampunk Vampire Girl has been thrown into The Dungeon of Despair (read Book One), lost in the past through The Tower Tomb of Time (read Book Two), and now she lives in a magical mansion that floats beneath a hot air balloon. On the outside it looks ordinary while the inside has numerous bewitched hallways like a maze and countless enchanted doors that lead anywhere in the world! But when two villains take over the Floating Mansion, Key works desperately to get it back with the aid of old friends like Miss Broomble the Witch, Mr. Fuddlebee the Ghost, and her new friend ARTH-R the Robot. However, the villains have a secret weapon: They know the location of Key's missing parents! In the end, she might win back not only her house, but also her home.