An impossible crime has occurred. A Treasury officer has vanished - abducted from an impenetrable tower. The brilliant but mercurial investigator, Ana Dolabra, and her assistant Dinios Kol have been called in to solve the mystery. When a body surfaces, it becomes clear that this is a case of murder. Worse, the killer seems to be able to pass through warded doors like a ghost, and can predict every move Ana makes. Ana's solved impossible cases before. But this time, with the stakes higher than ever and the investigators seemingly a step behind their adversary at every turn, has Ana finally met an an enemy she can't defeat?