The Year of the Locust by Terry Hayes

Publisher's Synopsis

If, like Kane, you're a Denied Access Area spy for the CIA, then boundaries have no meaning. Your function is to go in, do whatever is required, and get out again - by whatever means necessary. You know when to run, when to hide - and when to shoot.

But some places don't play by the rules. Some places are too dangerous, even for a man of Kane's experience. The badlands where the borders of Pakistan, Iran and Afghanistan meet are such a place - a place where violence is the only way to survive.

Kane travels there to exfiltrate a man with vital information for the safety of the West - but instead he meets an adversary who will take the world to the brink of extinction. A frightening, clever, vicious man with blood on his hands and vengeance in his heart...