The Seventh Doctor and Ace visit Bernice Summerfield at a physics lab, where she was dropped off to meet an old friend. Since the guy never showed up, Bernice has mostly spent her time at the lab being bored and helping out with garbage disposal.
The Doctor catches up with an old friend named Remnex, who immediately proceeds to get brutally murdered, and sends a distress signal back in time to the Doctor on his way there. Bernice, meanwhile, gets thrown down the garbage chute and ends up on the hellish planet below, where her lost friend (who was kidnapped and forced to do some emergency archaeology) also gets brutally murdered. His robot buddy Joseph, though, survives — albeit with a bit of Heroic BSoD at losing the man who programmed him.
The whole thing turns out to have been engineered by an Eldritch Abomination intent on destroying the known universe with the lab's physics experiments. He's spent quite a number of centuries surviving by means of Body Surf (and with the help of a nice big interstellar Cult). He effortlessly takes over Remnex' body and starts hypnotising people left and right, including Benny. With his original skull now having been excavated, he's about to use the Dark Flame to subdue all life and become a God-King. He also plans to use Benny's body as his next.
While Ace threatens to go suicide bombing, tries to snap Benny out of hypnotism and fights off animated skeletons with the Doctor's umbrella, the Doctor fuses Joseph's circuits to the MacGuffin (with Joseph making a Heroic Sacrifice in the process). When the Eldritch Abomination decides to engage in the Battle in the Center of the Mind with the Doctor, his Mind Rape fails rather spectacularly, and the Doctor — granted momentary Reality Warper powers — manages to fashion the whole thing into a rather more positive Close-Enough Timeline.
- Back from the Dead: The cult of the Dark Flame is dedicated to bring their master back to life.
- Call-Back: Black Light first made a TV appearance in The Mysterious Planet.
Bernice: "When I say run, run."
- And this little gem:
- Captain Ersatz: Joseph seems to have the mannerisms of C3PO.
- The Chessmaster: Seven, as per usual.
- Compelling Voice: The Doctor uses his to force Ace to sleep.
- Vilus Krull has one as well.
- Continuity Nod: Ogrons are namedropped.
- Heroic Sacrifice: Joseph makes one (though the Doctor promises he'll try to fix him up). Ace also wouldn't mind making one.
- Hypocritical Humor: The Doctor doesn't trust people who hide behind titles.
- Just One Second Out of Sync: A crystal and a skull exist "partially" out of the time continuum.
- Shout-Out: A Darth Vader quote.
- Single-Biome Planet: Of volcanic activity with acid storms. I heard it's lovely in the summer.
- Swashbuckler: Ace does this with an umbrella.
- Teleporters and Transporters: The Transmat system comes back, as a garbage disposal into the planet's surface.
- Took a Level in Badass: Ace spent some time with the military before this story. This makes her even more badass.