London can drain the life out of you.... Bob Howard is an intelligence agent working his way through the ranks of the top-secret government agency known as the Laundry. When occult powers threaten the realm, they'll be there to clean up the mess - and deal with the witnesses. There's one kind of threat that the Laundry has never come across in its many decades, and that's vampires. Mention them to a seasoned agent, and you'll be laughed out of the room. But when a small team of investment bankers at one of Canary Wharf's most distinguished financial institutions discovers an arcane algorithm that leaves them fearing daylight and craving O positive, someone doesn't want the Laundry to know. And Bob gets caught right in the middle.