The only way the Doctor can rescue Amy and Rory from a crashing space liner is to save the soul of a lonely old miser, Kazran Sardick, the richest man in Sardicktown.

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...

On Christmas Day in a remote human colony, the Doctor's help is requested by River Song and he finds himself in a chase across the galaxy to stop a robot bodyguard.

This Christmas, the Doctor comes face to face with, the Doctor! The first and current Doctors contemplate mortality in the Arctic as the join forces against a common enemy, revisit another last-of-its-kind being, and are ultimately responsible for the life of a WWI soldier.