Shadow Men of Crann features the second Doctor and his first two companions, Ben and Polly. This is actually a bit of a tall order as there are few of their episodes left to get any kind of grip on their relationship. The only episode I have actually seen in full with Ben and Polly is their first one, War Machines, with the First Doctor. I’ve not seen a full, existing story with the Second Doctor and those two companions. They’re all in the ‘missing’ folder.

But the general impression is that Polly was a sweet, smart thinking girl who The Doctor regarded very much as a substitute for his granddaughter – as he did with most of the companions. Ben was a man who generally thought with his fists. Nevertheless, The Doctor regarded him as trustworthy and reliable.

The Voord appeared in the First Doctor story Keys of Marinus as the sinister henchmen of the main bad guy, but it was always doubtful if they were natives of Marinus. A novelisation called The Fishmen of Kandalinga expanded on their history, but they are still something of a blank page. In particular I decided to make their black, shiny, wetsuit into an exo-skin because there was no reason not to think that was what it was. This allowed for them to use technology to turn the humanoid Crann men into a Voord slave class, and for The Doctor to find a way to partially restore them.

Crannogs are exactly what this story describes, although usually a bit less elaborate than the ‘wheel’ of islands joined by bridges. They are commonly found in Ireland and Scotland and were used for defensive purposes. The Irish and Scottish ones are normally in lakes. The idea of dozens of them dotted about an ocean was a variation on the theme, too. Incidentally, I wasn’t even remotely thinking of Kevin Kostner’s Waterworld at any point. That didn’t even occur to me until after I had finished writing the story.

http://tardis.wikia.com/wiki/Voord
http://en.wikipedia.org/wiki/The_Keys_of_Marinus
http://tardis.wikia.com/wiki/The_Fishmen_of_Kandalinga
http://en.wikipedia.org/wiki/Crann%C3%B3g

http://tardis.wikia.com/wiki/Polly
http://tardis.wikia.com/wiki/Ben_Jackson