After the dramatic events of The Creeping Shadow, the Lockwood team (plus Quill Kipps) deserve some well-earned rest. So naturally they break into the Fittes Mausoleum, on a perilous mission to discover the truth about London's top ghost-hunting agency, and its sinister leader. What they discover will change everything. But there's little time to ponder. A near-miss at a haunted fairground is only the start - as the Fittes agency closes in on the team, an epic struggle commences. With the help of some unexpected, and rather ghostly, allies, Lockwood & Co must battle their greatest enemy yet, as they move ever closer to the moment when the earth-shattering secret of 'the problem' will finally be revealed. Jonathan Stroud once again delivers a rousing adventure full of danger, laughs, twists, and frights. The revelations will send readers back to Book 1 to start the series all over again.