Alastair Reynolds 
Absolution Gap 

Take another awe-inspiring leap into the darkly imagined future of REVELATION SPACE, where it is time for Humanity to meet its Unmakers.Mankind has endured centuries of horrific plague and a particularly brutal interstellar war … but there is still no time for peace and quiet.Stirred from aeons of sleep, the Inhibitors – ancient alien killing machines – have begun the process of ridding the galaxy of its latest emergent intelligence: mankind. As a ragtag bag of refugees fleeing the first wave of the cull head towards an apparently insignificant moon light-years away, they discover an avenging angel, a girl born in ice. She has the power to lead mankind to safety, and the ability to draw down their darkest enemy.And on a planet where vast travelling cathedrals crawl towards the treacherous fissure known as Absolution Gap, an unsettling truth becomes apparent: to beat one enemy, it may be necessary to forge an alliance with something much, much worse …