From award-winning science-fiction writer Alastair Reynolds, a spellbinding new adventure featuring the Third Doctor. After billions of years of imprisonment, the vicious Sild have broken out of confinement. From a ruined world at the end of time, they make preparations to conquer the past, with the ultimate goal of rewriting history. But to achieve their aims, they will need to enslave an intellect greater than their own... On Earth, UNIT is called...