It's subtle.. But one of things that really captures this piece for me are the lines. They all seem to draw in toward the Doctor. Whether it's the pinstripes on his suit, the texture of the dirt, or the texture of the floor tiles.. Everything seems to subtly converge on the Doctor. A nice touch!
I can't remember (it was 2006) I'll dig the storybook out and reread it. Something about a man who lives alone but always feels that there is something lurking behind him, and converses and explains his fears to a girlfriend via pm's on a computer, but the truth is revealed to be something to do with dusty old photographs and a body in the cellar. I think.
It was a Stephen Moffet story (new producer of Dr Who) and it was very good, although both the storybook editor and myself were in agreement that it had more than a hint of the macabre Sapphire and Steel episodes about it.