The Nightmare Stacks (Laundry Files, #7) by Charles Stross

The Laundry Files’ “fast-paced blend of espionage thrills, mundane office comedy and Lovecraftian horror” (SFX) continues as Hugo Award-winning author Charles Stross assigns a day trader to a permanent position on the night shift…

After stumbling upon the algorithm that turned him and his fellow merchant bankers into vampires, Alex Schwartz was drafted by The Laundry, Britain’s secret counter-occult agency that’s humanity’s first line of defense against the forces of darkness. Dependent on his new employers for his continued existence—as Alex has no stomach for predatory bloodsucking—he has little choice but to accept his new role as an operative-in-training. 

Dispatched to Leeds, Alex’s first assignment is to help assess the costs of renovating a 1950s Cold War bunker into The Laundry’s new headquarters. Unfortunately, Leeds is Alex’s hometown, and the thought of breaking the news to his parents that he’s left banking for civil service, while hiding his undead condition, is causing more anxiety than learning how to live as a vampire secret agent preparing to confront multiple apocalypses.

Alex’s only saving grace is Cassie Brewer, a drama student appearing in the local Goth Festival who is inexplicably attracted to him despite his awkward personality and massive amounts of sunblock. 

But Cassie has secrets of her own—secrets that make Alex’s night life behaviors seem positively normal…