The BBC Media Centre has released the official synopsis for the twelfth and final episode of the current series of Doctor Who, read on for further details:
DEATH IN HEAVEN - by Steven Moffat
With Cybermen on the streets of London, old friends unite against old enemies and the Doctor takes to the air in a startling new role. Can the mighty UNIT contain Missy? As the Doctor faces his greatest challenge, sacrifices must be made before the day is won.
Doctor Who: Death in Heaven will broadcast Saturday 8th November at 8:00pm on BBC One and BBC One HD.