The labyrinth index - Charles Stross

Britain is under New Management. The disbanding of the Laundry - the British espionage agency that deals with supernatural threats, has culminated in the unthinkable - an elder god in residence in 10 Downing Street.

But in true 'the enemy of my enemy' fashion, Mhari Murphy finds herself working with His Excellency Nylarlathotep on foreign policy - there are worse things, it seems, than an elder god in power, and they lie in deepest, darkest America.

A thousand-mile-wide storm system has blanketed the midwest, and the president is nowhere to be found - Mhari must lead a task force of disgraced Laundry personnel into the storm front to discover the truth. But working for an elder god is never easy, and as the stakes rise, Mhari will soon question exactly where her loyalties really lie.