Frayed

"I like to stare into the sun, eyes wide. It burns incredible colours into my head, great shifting continents of them that blot out all else. And I try to keep looking until I imagine all the pretty blue has boiled away from my eyes and they are left a bright, bloody red and quite sightless." On a blasted world, the Doctor and Susan find themselves in the middle of a war they cannot understand. With Susan missing and the Doctor captured, who will save the people from the enemies from both outside and within?