This was one story I DID change slightly because of details that came to light in the 2006 series. The double episode Rise of the Cybermen/Age of Steel and then later, Army of Ghosts and Doomsday, made it clear that travelling between alternative universes wasn’t something that should be done casually. So I changed the first and last scenes. In the first, they were supposed to be travelling to the place where the rift between the universes was, and Rassilon in the end was going to help TEN get back there. Instead, I had them simply going to an agreed place, the space equivalent of a lay-by on the dual carriageway, before parting. And in the final scene, Ten refuses Rassilon’s offer to send him back to his own universe because he has nothing to go back for and wants to stay here where he has friends. The possibility of future Two Doctor stories is set up as well as the idea that Rassilon might prove an ally to them both.

Putting Nine and Ten together is very satisfying for me as a writer. The two characters bounce off each other very well, and it would have been very tempting to write a few more. I had to be strict and ration them. This is the last double act until a very small scene in the last Unfinished Business story, though Nine joins Ten in his stories for a different perspective on the same idea.

The long introduction where the two of them talk about the Laws of Time and just how many they had broken, was inspired by a partial list of those laws which I found online on a website that no longer seems to exist. They were an interesting collection that made for a very strict set of rules that The Doctor’s rebel nature could never completely go along with. The grandfather paradox and the lottery rule are about the only ones he would not have broken. Although, in fact, Ten DID break the lottery one slightly in School Reunion, when he gave a winning ticket to a teacher in order to get her job temporarily.

As for the Dark Matrix and Shada, these both draw upon ideas from the classic series. The Matrix was the repository for Time Lord wisdom long before the American movie of the same name. The fact that the Time Lord Matrix allowed people to step into an unreal world that FELT and looked real is, I trust, complete coincidence. Or if it isn’t, Doctor Who had the idea FIRST.

A dark matrix of the minds of Gallifrey and the universe’s worst scum is the antithesis of that. And where else would it be but Shada.

Shada, the lost prison planet, from the lost episode of Doctor Who. There was a virtual blank page to be written. The only certain thing about it was that it was a cryogenic prison. The criminals were kept in suspended animation and guarded by robots. Beyond that, the imagination could fill in the blanks. In my imagination it WAS a bit different from the images in the animated telecast. There was the sort of gate that there would have been at Auschwitz or some such place because it has that sort of horror as a place of detention. I added the court on the MOON of Shada because there is no reason why it shouldn’t be.

The Rani as a malevolent ghost was a flash of inspiration. As portrayed by Kate O’Mara she was a real femme fatale. Making her a larger than life apparition increased her malevolence and sets up the antagonism between her and The Doctor. But she is only a minor character here. Beyond her is the real evil, represented by the dark, black floor that was not solid and not liquid.

Lissandro Harpaindrix Gellovia, for whim you can’t get pills, was an example of the Gallifreyan criminal scum. Obviously a rapist, but I tried to avoid using words like that in a story aimed at a PG readership. So his evil had to be implicit rather than explicit. But I think he comes across as a thoroughly no good sort.

But the real bad guy is the ultimate Time Lord Renegade. The Master returns – briefly at least. Before being defeated by the combined efforts of two Doctors and Rose. His explanation of how he got to Shada is a bit shaky scientifically, but Doctor Who is never 100% science fact.

http://www.bbc.co.uk/doctorwho/classic/episodeguide/shada/

http://en.wikipedia.org/wiki/Shada