A mischievous Castle Zombie twin named Lacuna wants her dull existence fixed and talks the reluctant magician-in-training Grey into helping her outwit Xanth's all-knowing book of answers. The bargain sends her to the ailing Good Magician Humfrey, who needs someone to record his own tangled life story — and the history of his five wives — before a waiting demon will listen. The fourteenth Xanth novel turns a favor into an oral history.
Summary by Loreful, from public sources