Cold Blood - by Chris Chibnall
It is the most important day in the history of Earth: the dawn of a new age of harmony or the start of its final war.
In the latest episode of the time-travelling drama, the Doctor must face his most difficult challenge yet. It is a battle in which he cannot take sides and a day when nobody must die...
Doctor Who: Cold Blood will broadcast on Saturday 29th May at 6:25pm on BBC One and BBC HD.