It's the 22nd century. To drum up interest in the boring old solar system, a consultant has been brought in to improve its feng shui by clearing away some of the less interesting celestial bodies. In the midst of all this, the Doctor, Fitz, and Trix arrive, looking for some mercury to repair the TARDIS, and quickly become embroiled in events.
Tropes present in Camera Obscura include:
- Abhorrent Admirer: The Doctor wreaks terrible and vicious revenge on Falsh by brainwashing a fishman to fall in love with him.
- Always Camp: Halcyon, a decoratiste, who's a huge ham and wears various really outlandish outfits. Plus he gets rather flirty with Fitz.
- Brainwashed and Crazy: The space slugs cause people to start mindlessly attacking each other.
- Closed Circle: The Doctor needs mercury to repair the TARDIS's fluid links. Until he finds some, he and his companions are pretty much stuck going along with things.
- Continuity Porn: Explained in the author's note. The premise of this book exists to explain some dodgy science from Revenge of the Cybermen, where the Doctor claimed that Jupiter only has twelve moons.
- Disabled Means Helpless: Halcyon, who's blind, depends on his assistant Sook to do a lot of things for him. The Doctor quickly loses patience and takes a tough-love approach.
‘If you see someone, if there’s danger... you will tell me, won’t you?’ Halcyon grabbed hold of the Doctor’s wrist. ‘Only I shan’t be able to cope alone...’
‘You’re blind, man, not helpless!’ he exploded. But he lowered his voice as they stepped out on to the NewSystem reception. ‘I’m sorry. Please believe me, I shan’t abandon you, Halcyon.’
- Drugs Are Bad: The Doctor is a bit of a moral relativist about recreational drug use, but Fitz and Trix are both appalled to find that heroin is legal and common in the future. The narrative seems to back them up, considering the fact both of the characters who are seen using it end up dead.
- Earth That Used to Be Better
‘Earth’s mined out. Stripped down. Washed up. We all buggered off and left the leftovers to the Third World lot. They’re living pretty much the same as they always have done.’
- High Times Future: Heroin is legal in the future.
- I Kiss Your Hand: The Doctor kisses Fitz's hand in this one. Bless.
- Throwing Off the Disability: Halcyon's blindness is cured as an "unexpected side effect of the psychic attack".