Another in Green's Secret Histories series about Eddie Drood, aka Shaman Bond (For Heaven's Eyes Only, 2011, etc.), set in the same universe as his Nightside yarns and occasionally intersecting with them.
The Drood family protects humanity against such outside threats as the Hungry Gods and the Apocalypse Door. Droods in good standing with the family are gifted with various superpowers and an impenetrable suit of golden armor that manifests on demand. Some time ago Eddie left Drood Hall and became a field agent operating in London. This time, arriving at Drood Hall with his girlfriend/sidekick Molly Metcalf, a powerful witch, Eddie is aghast to find the heavily defended ancestral pile an utter ruin; even his armor no longer works. After surveying the wreckage, and pocketing the Merlin Glass, a handy space/time wormhole, Eddie realizes that this isn't his Hall at all, but a duplicate. The real Hall has been sent—somewhere—by means of the dimensional engine Alpha Red Alpha, to which only a family traitor could have had access. Hundreds of pages slouch by while Eddie and Molly indulge in numbing banter and Eddie enlarges on his powerful and noble and complicated and entirely too numerous family. Finally, he decides without any evidence that the culprit must be Crow Lee, the Most Evil Man in the World. In order to track down Crow Lee, however, our heroes must find their way to the Department of the Uncanny, where the Regent of Shadows is sure to know Lee's whereabouts. What action there is consists mostly of bodies of various shapes and sizes exploding into gobbets of flesh and sprays of blood, and for even the most avid readers this sort of thing quickly palls.
Let your path lead you to the Nightside series, which has everything—real wit, personalities, plot, invention—that this book does not.