The Eighth Doctor, Charley and C'rizz are just going about their normal lives in the TARDIS, until Charley opens a box in C'rizz' bedroom out of curiosity. She's immediately dragged into a mindscape of screaming terror. To make matters worse, the TARDIS is transported across space-time beyond a barrier of something and starts to violently rearrange her own interior. The voices of the dead cry out in everyone's minds, and the Doctor becomes pretty convinced that they've reached hell itself. Also, C'rizz is dragged through a crack in the TARDIS console room floor, and the TARDIS' central column begins to fill up with blood — human blood — until it shatters.
The Doctor's quick to realise that the TARDIS is just communicating her need to take a break and repair herself. So, hoping that C'rizz is still alive and hopefully even inside the TARDIS somewhere, they exit onto the alien planet they've landed on. And immediately get captured by the local medieval-style population. The TARDIS turns herself to stone, which the Doctor suspects is just to keep herself safe for a while.
C'rizz, meanwhile, isn't in the TARDIS anymore, but outside on the planet — beyond the barrier. He meets a man, Aboresh, who's been talking to him in his dreams. Aboresh tells about a disaster that happened 900 years before and devastated the planet. C'rizz will be their grand messiah, will become a Reality Warper and will sacrifice himself to the great beast. And indeed, C'rizz soon learns to manipulate the world around him freely, and turns the TARDIS to stone in order to prevent his friends from leaving.
Charley befriends Lolanthia, the teenaged daughter of leader Cacothis. It's explained that the Citadel is protected from the monsters outside the barrier. She soon realises that Lolanthia is a whole lot older than she looks. By a few centuries, in fact. When C'rizz appears to her in a dream, Charley urges the Doctor to go investigate the Citadel a bit more thoroughly, and the two of them discover technology that's decidedly not medieval. Meanwhile, a massive Eldritch Abomination of a beast (Borarus) appears on the horizon outside the barrier. It's revealed that Cacothis and his people are ancient scientists, who were accidentally made immortal (painfully so) after some Applied Phlebotinum involving dimensional engineering led to a Negative Space Wedgie. Aboresh, a fellow scientist who was sleeping with Cacothis' wife, sabotaged the project and caused the accident when Cacothis found out and fired him.
The Beast Borarus is still roaring outside, as a giant amoeba, and the Doctor soon realises that the barrier can be breached... by people of the same race as the inhabitants of the Citadel. Which means that a humanoid monster chained up in the Citadel, who's been there for centuries, is actually just a mutated person... specifically, Cacothis' wife, Lolanthia's mother. Lolanthia goes into a massive Heroic BSoD at the discovery and decides to simply nuke everything, merging the genes of the Outlanders with those of anyone left in the Citadel. The Doctor, who pretty much anticipated that, explains he's already rigged a delay into the device, but he and Charley still have to be very quick. They eventually reach C'rizz, who's rapidly being transformed into a malicious Reality Warper against his will... and discover that the Beast Borarus is made up of all the souls that C'rizz has been a vessel for all along. They elected to be Sealed Inside a Person-Shaped Can upon dying, rather than face permanent death, and created C'rizz as a living phylactery to their entire race. C'rizz is horrified to discover he's a construct and decides to commit Heroic Suicide in order to stop the Beast. He turns into dust in Charley's hands.
Charley is completely traumatized by seeing her friend die. The Doctor, however, being somewhat desensitized to the experience of having a friend die (it has already happened to him quite a few times at this point, mind you), takes it all in his stride and, once again, simply tries to cheer his companion up a bit. He's kind of glad, actually, that C'rizz has found peace, because C'rizz just never quite fit into his team. Now things can go back the way they were — just him and Charley in the TARDIS. Charley, appalled by his attitude, tells him to drop her off on Earth, since she's not willing to spend another day with someone who's that heartless.
- A God Is He
- Artificial Human: Well, Artificial Eutermesan, created to trap the souls of the dead inside himself and hopefully transport them to a form of eternal life in order to escape death for the entire race. C'rizz has no idea.
- Broken Masquerade: The Doctor and Charley find out about C'rizz'... less morally sound habits.
- Call-Back: The Doctor and Charley walk into another console room, suggested to be the one from The Masque of Mandragora.
- The Doctor thinks the TARDIS turning to stone might the Chameleon circuit kicking in.
- Before dying, C'rizz mentions going to meet L'da.
- Casual Danger Dialogue:
- C'Rizz: Well, eh, excuse me, while I eh, run for my life.
- Clarke's Third Law: Charley invokes it in order to appear as wizards.
- Clock Roaches: Hellions.
- Crowd Chant: Happens in episode 1 under the direction of Aboresh.
- Cruel Mercy: Cacothis hopes Borarus destroying them will be this.
- Deus ex Machina: The Doctor calls C'rizz this, as he saves him and Charley.
- Disney Villain Death: Phelgreth gets knocked off a cliff by a Black Angel.
- Drunk with Power: C'Rizz takes to being a Reality Warper a bit too quickly.
- Evil Mentor: Aboresh turns out to be this to C'rizz.
- Griping About Gremlins: Hellions, though the Doctor says "we"'d call them Gremlins, are attracted to chaotic eddies in the timestream. The TARDIS breaking down attracts a bunch of them.
- Half the Man He Used to Be: Cacothis tells the Doctor he was bisected.
- Healing Factor: Of sorts. Nothing can ever change.
- Hearing Voices: C'rizz.
- To Hell and Back: The Doctor believes the anomaly might be the origin of all forms of Hell known to man.
- Hoist by His Own Petard: Phelgreth kills Cocathis, causing the Black Angel that used to be Cocathis' wife to attack him, and fall to his death.
- I Don't Like the Sound of That Place: The Woods of Suicides.
- C'rizz: Charming name.
- "I Know You Are in There Somewhere" Fight: The Doctor tries to pull an indirect version of it. He claims C'Rizz isn't being controlled and asks him to not absorb Charley, but just him instead. ... He doesn't.
- Immortality Hurts: With plenty of gore.
- Mind Control: C'Rizz learns how to exert his will over more primitive creatures.
- No Body Left Behind: C'Rizz crumbles to dust after his death.
- Older Than They Look: The people in the anomaly.
- Phlebotinum Overload: Resulting in a Negative Space Wedgie.
- Power Echoes: Once C'Rizz has reached his full potential.
- Prophecies Are Always Right
- Reality Warper: C'rizz becomes one.
- The Reveal: We finally discover just what C'rizz is.
- Secret Underground Passage: Behind a mirror.
- Sealed Inside a Person-Shaped Can: The Eutermesans, inside C'rizz.
- Seven Deadly Sins: The Pride of Cocathis led the world to its downfall.
- Schizo Tech: Medieval robes... and dimensional technology.
- Take a Third Option: C'Rizz chooses not to execute his mission, and chooses death over killing the Doctor and Charley.
- Those Two Guys: Phelgreth and Straith.
- Was Once a Man: Cacothis' wife is the Black Angel from the Cold Open.
- Wham Episode: C'rizz dies. Then, the Eighth Doctor shows no sympathy over his death, causing Charley to ship off before he can even blink.
- What the Hell, Hero?: In the end, the Doctor accepts C'rizz' death without a second thought, and even seems glad that life in the TARDIS is back to normal: just him and Charley. Charley's so horrified by his behaviour that she tells him to drop her off on Earth. The scene strongly echoes Six' actions in "Project: Lazarus".