It is the 10th Doctor's final novel in the New Series Adventures (not including original audio books or Code of the Krillitanes).
Synopsis
The Doctor arrives in Worcester in 1139. There have been disappearances in last few months and people live in terror, afraid to leave their dwellings once the dark falls. When the Doctor meets with a Krillitane, he knows they have every reason to be afraid.
Background
Though there is no official companion featured in the novel, there are guest companions named Emily and captain James Darke.[1]