What does a book fair, a set of unicorn tarot cards, and a ghost have in common? Something sinister is in the works.

When Nana takes teenage Carmen and Hester to a very special once-in-a-lifetime local book fair expecting to help them grow in their craft, they discover wicked witches at work. And when Carmen discovers she can communicate with spirits, the situation becomes deadly.

With help from Nana, a girl named Mira, and a man with a funny mustache, will Carmen solve her first mystery in time to save one of their own?