Wormwood . . . the bright star shall fall from the sky . . . and many will die from its bitterness . . . London 1756. In a Bloomsbury attic, Royal Society astronomer Dr Sabian Blake has made an extraordinary discovery. In the Nemorensis, an ancient leather-bound book that holds the secrets of the universe, a scribbled message tells of a devasting comet that will one day bring death and destruction to the city. Now the ancient prophecy has come to pass and the comet has arrived, a harbinger of doom for the city and all who live there. Only by deciphering a mysterious message held within the Nemorensis can Blake hope to avert the catastrophe. But circling in the shadows there are others interested in the Nemorensis too, for more sinister reasons . . . A breathtaking and thrilling novel of historical intrigue, dark magic and the supernatural from the author of the international bestseller Shadowmancer.