In December, the Doctor and Raine will face their ultimate test; UNIT will be stretched to breaking point by a series of alien invasions and a secret as old as the Time Lords themselves will finally be told.

It’s Big Finish’s UNIT: Dominion.

The Universe stands on the brink of a dimensional crisis – with the Doctor (Sylvester McCoy) and Raine (Beth Chalmers) pulled right into the epicentre.

On Earth, UNIT Scientific Advisor Dr. Elizabeth Klein (Tracey Childs) and a hitherto unknown incarnation of the Doctor must use all their resources and collective powers to fight off a series of increasingly bizarre alien invasions.

At the heart of it all lies a terrible secret. Reality is being torn apart and the two Doctors, Raine, Dr. Klein and UNIT are all that stand between salvation and the end of the universe itself.

Co-written with Jason Arnopp and directed by Nicholas Briggs UNIT: Dominion is available to pre-order now for £30 as a five disc set and as a digital download for £25.