Lies Sleeping, by Ben Aaronovitch

Now a detective, Peter Grant is a key member of the task force trying to thwart the twisted ambitions of Martin Chorley, aka the Faceless Man. The action is all centred around St Paul’s, in the heart of the City of London, with Chorley trying to harness the power of an ancient vengeful spirit. Can Peter persuade former colleague Lesley to repudiate her allegiance to the dark side and help defeat it, or will she double down? The Met has finally thrown substantial resources at the Folly – magic HQ, but all that Peter loves is at risk and it will take all of his alliances to overcome this most formidable adversary. The fight takes even more of a toll than usual, but there is promise for the future too, both personally and professionally.