Ghouls and spectres beware! London's smallest (but best) psychic detection agency Lockwood & Co. is back with a fourth deliciously terrifying tale! Lucy has left Lockwood & Co. A freelance operative, she is hiring herself out to other agencies - agencies that might value her ever-improving skills. But now Lockwood needs her help. Penelope Fittes, leader of the well-renowned Fittes Agency wants Lockwood & Co. - and only them - to locate and remove the 'Source' for the legendary Brixton Cannibal. It's a tough assignment. Made worse by the tensions between Lucy and the other agents - even the skull is treating her like a jilted lover! What will it take to reunite the team? Black marketeers, an informant ghost, a Spirit Cape that transports the wearer, and mysteries involving their closest rivals may just do the trick.

But not all is at it seems. And it's not long before a shocking revelation rocks Lockwood & Co. to its very core . 'Stroud is a genius' - Rick Riordan, author of the Percy Jackson series.