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. . . .
As a massive outbreak of supernatural Visitors baffles Scotland Yard and causes protests throughout London, Lockwood & Co. continue to demonstrate their effectiveness in exterminating spirits. Anthony Lockwood is dashing, George insightful, and Lucy dynamic, while the skull in the jar utters sardonic advice from the sidelines. There is a new spirit of openness in the team now that Lockwood has shared some of his childhood secrets, and Lucy is feeling more and more as if her true home is at Portland Row. It comes as a great shock, then, when Lockwood and George introduce her to an annoyingly perky and hyper-efficient new assistant, Holly Munro.
Meanwhile, there are reports of many new hauntings, including a house where bloody footprints are appearing, and a department store full of strange sounds and shadowy figures. But ghosts seem to be the least of Lockwood & Co.'s concerns when assassins attack during a carnival in the center of the city. Can the team get past their personal issues to save the day on all fronts, or will bad feelings attract yet more trouble?
Danger abounds, tensions escalate, and new loyalties form in this third delightfully terrifying adventure in the critically acclaimed Lockwood & Co. series.