The BBC have released the official story synopsis for Death in Heaven the twelfth episode and 2nd part of the Series 8 finale, written 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. Guest stars: Michele Gomez, Chris Addison, Sanjeev Bhaskar, Jemma Redgrave, Ingrid Oliver

It premieres Saturday 8 November with the time to be confirmed on BBC1.