Supernatural detective R. F. Jackaby and his ever-persistent assistant Abigail Rook continue their most serious investigation. This time, the fate of the entire human race is at stake! The streets of New Fiddleham are flooded with nightmarish creatures from the other world, but they are only puppets in the hands of a mysterious Dark King.
Jackaby and Abigail enlist the support of Arawn, ruler of benevolent faeries, and try to prevent a catastrophe. And then the mayor of Spade announces a hunt for supernatural beings… Detective Jackaby’s adventures and his loyal assistant have never been this dangerous!