In this thrilling addition to Lockwood & Co series, a terrible crime forces Lockwood to turn to Lucy for help, setting them on the trail of dark secrets at the heart of London society--both professionally and personally, their investigation stirs up forces they may not be able to control . After leaving Lockwood & Co. at the end of The Hollow Boy, Lucy is a freelance operative, hiring herself out to agencies that value her ever-improving skills. One day she is pleasantly surprised by a visit from Lockwood, who tells her he needs a good Listener for a tough assignment. Penelope Fittes, the leader of the giant Fittes Agency wants them--and only them--to locate and remove the Source for the legendary Brixton Cannibal. They succeed in their very dangerous task, but tensions remain high between Lucy and the other agents. Even the skull in the jar talks to 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 Steve Rotwell and Penelope Fittes just may do the trick.

But, in a shocking cliffhanger ending, the team learns that someone has been manipulating them all along .