There is a reason for the “?” in the “Invisible Enemy?” title. The word “enemy” is being questioned. Because everyone assumed that an invisible spaceship must be an enemy. But not necessarily. The Doctor, after all, has a disguised spaceship and he isn’t an enemy.

But the story begins with the first of several reunions for The Doctor. First, with two people he met in the story “Panem et Circenses” Miss Watling, the local journalist who would give Sarah Jane a run for her money and Araminta Rawlings the Goth teenager, now nineteen and calling herself Susan, her real name, again, and working with Miss Watling at the local paper. The Doctor is thrilled to meet them both on the same mission as he is. He is thrilled, later, to find Sarah Jane Smith, also on the case. He is LESS thrilled to meet Harriet Jones. When I wrote this story we didn’t quite know what had happened to Harriet Jones after his ‘six words’ that would take down he government in his universe. We now know that her government failed and Harold Saxon stepped into the breach, making The Doctor realise he should leave politics alone. But that was in his own universe. Here in Nine’s universe Harriet is still Prime Minister and she has not lost his friendship with him. She comes close in this story to making the same mistake that lost it in the other universe, but fortunately, listens to him.

Sarah Jane’s story is different in this universe, too. Here, she has married Harry, and, though he is dead now in this timeline, she HAS at least known several years of happiness with him, whereas the Sarah Jane of his universe stayed alone all he life, with some underlying bitterness about why he didn’t come back for her. These two differences serve as a reminder that he IS in a different universe ever since the Unfinished Business story last New Year which introduced the concept.

I was a little vague about exactly where these events were taking place. The space ship was located on Horse Bank, off Southport in Lancashire, the other side of the Ribble Estuary to Blackpool. Southport is a seaside resort with a pier and promenade, arcades, shopping, Southport Rock, fish and chips, etc. But it is also a place with some fantastic sand banks where the estuary becomes the Irish Sea, wild places that could almost look like alien landscape without Blackpool Tower in the distance to keep your imagination on the ground. The sandbanks have all sorts of whispers about them, of quick sands and places where foolish people are cut off and drowned in seconds as dry land becomes sea. The road The Doctor walks along at first is a sea defence holding back the tide from acres of reclaimed farm land and there are marshlands with rare and protected bird life in them. It is a fabulous place, more remarkable for being within a stone’s throw of a commercial seaside resort, of major cities and towns. And it was crying out for a story to be set there. I’m not sure if I captured it EXACTLY. If not, never mind. The story took over the landscape that actually inspired it.

And at the end of it, The Doctor has a new companion, a new SUSAN. Because he feels he NEEDS a Susan about the TARDIS.

Get the hybrid map here for an idea of what the sands are like.
http://maps.google.co.uk/maps?q=Southport,+United+Kingdom&sa=X&oi=map&ct=title

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

http://www.webbaviation.co.uk/southport/southport.htm