Written by Gary Russell; published 2005, and featuring the Sixth Doctor and Mel.
Carsus: the largest repository of knowledge in the universe — in any universe, for there is an infinite number of potential universes; or rather, there should be. So why are there now just 117,863? And why, every so often, does another one just wink out of existence?
The Doctor and Mel arrive on Carsus to see the Doctor's old friend Professor Rummas — but he has been murdered. Can they solve the mystery of a contracting multiverse, and expose the murderer?
With the ties that bind the Lamprey family to the past, present and future coming unravelled around him, only the Doctor can stop the descent into temporal chaos. But he is lost on Janus 8. And Schyllus. And a twentieth-century Earth where Rome never fell. And...
Tropes:
- Alternate History: As a multiverse-focused story, we naturally get a whole bunch of these, the most prominent being one where the United Kingdom is ruled by a still-extant Roman Empire, and where it was Peri who sacrificed herself to save the Doctor (albeit the Sixth rather than the Fifth, and not at Androzani Minor), rather than the other way around.
- Apocalypse How: A whole bunch of alternate universes are destroyed before the story even gets underway, and more perish during the story's events. Though it's vaguely implied that Monica Lamprey's destruction may restore all the universes she destroyed.
- Back for the Finale: During the final battle, alternate versions of Peri, Evelyn Smythe, and even Frobisher the Penguin accompany the various other Sixth Doctors.
- Canon Discontinuity: The Past Doctor Adventures' place in canon has always been nebulous at best, but this is one of the few stories to have been firmly rendered non-canon, with its events superseded by Big Finish's "The Last Adventure".
- Dark Secret: Mel's is revealed to be that when she was 18 months old, she accidentally killed her older sister by unwittingly tripping her up and causing her to break her neck after falling down a flight of stairs.
- Fix Fic: The story is another attempt to give the Sixth Doctor a more satisfying send-off than his notorious death in the Cold Open of "Time and the Rani".
- Going to Give It More Energy: This ends up being how the Sixth Doctors destroy the Monica Lamprey, sacrificing their chronon energy and over-feeding her until she's destroyed.
- Half-Human Hybrid: One of Mel's alternate reality counterparts is half-human, half-Silurian.
- Heroic Sacrifice:
- A whole bunch of Sixth Doctors give their lives to take out the Monica Lamprey. Our universe's Sixth Doctor doesn't die immediately, but his body suffers irreparable damage, leading to his regeneration into the Seventh Doctor. Most of the other Sixes end up being disintegrated before they even have the opportunity to regenerate into a Seven.
- Helen Lamprey helps the Sixth Doctor(s) to destroy Monica Lamprey, knowing that doing so will cause herself to be erased from existence as well.
- Shut Up, Hannibal!: Mel physically shuts up the Monica Lamprey, punching her in the face in response to a Hannibal Lecture over being responsible for her sister's accidental death.
