The BBC Media Centre have issued the synopsis for the twelfth and final episode of the current series of Doctor Who:
HELL BENT - by Steven Moffat
If you took everything from him, betrayed him, trapped him, and broke both his hearts…how far might the Doctor go? Returning to Gallifrey, the Doctor faces the Time Lords in a struggle that will take him to the end of time itself. Who is the Hybrid? And what is the Doctor’s confession?
Doctor Who: Hell Bent will broadcast on Saturday 25th December on BBC One and BBC One HD, a time is to be confirmed.