Some time after leaving Cassie in Norway, the Sixth Doctor has perfected his cure for her vampirism, and steers the TARDIS back to around ten minutes after he and Evelyn left her. The TARDIS disagrees a bit and suggests meeting her months later, in the south of Norway, instead.
The Doctor decides to follow the TARDIS' advice and vworps back into Cassie's life later than originally agreed on. She's really not happy with this. Months of being alone in the dark, surviving on rat blood, fleeing from overly enthusiastic vampire hunters and trying to cope with the cold — vampires can feel the cold, which the Doctor hadn't really considered — have left her desparate and bitter. In the middle of all that, a gentle, small blue alien appears, tries to defend itself from a hunter, and ends up being used by Cassie as a murder weapon.
As it turns out, Cassie has been scouted out by Nimrod again, and he's used her weakness and despair to brainwash her. She's part of the Forge now. Evelyn and the Doctor are taken captive and brought to the Forge, where the Doctor promptly gets Strapped to an Operating Table and tortured to the brink of death as part of a Forge project to recreate regeneration. Evelyn, meanwhile, tries to get through to Cassie. But the only thing Cassie is interested in is Evelyn's reason for wanting to travel with the Doctor... she has a serious heart condition (which Cassie's vampire ears easily pick up on), and the university was threatening to force Evelyn into retirement. The Doctor showing up gave her the perfect opportunity to see the universe while she still can. Evelyn is distraught to be confronted with her secret by an unsympathetic Cassie. Evelyn talks with Cassie further to try to figure out what caused her heartlessness and realises that she has been forced to forget about her young son, Tommy. Cassie is eventually able to remember him — with some coaxing from Evelyn — and is furious. After helping to free the Doctor, she attacks Nimrod but is promptly being shot straight through the heart with one of his crossbow bolts. Although the Doctor and Evelyn manage to escape from the Forge, Evelyn can't cope with Cassie's death, and breaks down sobbing. The Doctor, helpless, has no clue how to cope with the situation and simply tries to offer her some chocolate. In sorrow, she tells him that there are things that can't be fixed with chocolate, and she needs to be alone for a while, and their story is To Be Continued in "Arrangements For War". As for little Tommy...
Three and a half years later from Nimrod's perspective, and many centuries later for the now-Seventh Doctor, he happens upon the Forge again. Inside, he finds the Sixth Doctor working for Nimrod, claiming to have a plan — but unable to explain it.
Nimrod plans to use the gentle blue alien found in Norway, dubbed a Huldra after Norse legend, to open up an interdimensional portal. The rest of its species is just beyond space/time. When the Seventh Doctor decides to let them through, they retaliate to avenge the first Huldra's murder, instead of (as the Doctor had hoped) calmly engaging in diplomatic discussion. In the process, they rip Six's arm off.
The Seventh Doctor, who was already suspicious, definitely doesn't remember losing an arm, so he quickly figures out that Six isn't Six. He's a clone, one of three created by Nimrod to figure out the secret of regeneration. And to create an army of regenerative clones — Project: Lazarus. The two other clones died fairly quickly, one from a hearts attack because it wasn't viable, and one by having its throat slit by Nimrod in a failed attempt to induce regeneration. The remaining clone has all of Six's memories and personality, however, and is able to make "Contact!" with Seven, who's filled in on the rest of the story in the process.
The Huldra turn out to have a collective nervous system and telepathic pain receptors, which explains their aggression. Nimrod discards the plan to use them when he realises how weak that makes him. While Seven prepares to blow up the base, Clone-Six finds a room full of failed, mutated and discarded (but still conscious) versions of himself and learns that he's not the third clone. He’s one of hundreds, only three days old and already dying due to rapidly degenerating DNA and full of implanted memories from previous clones. After a brief Heroic BSoD, he commits a Heroic Sacrifice and goes down along with the Forge.
The Seventh Doctor is quite shaken by the whole experience, and decides that maybe, it's time for him to go home.
Tropes:
- An Arm and a Leg: The Seventh Doctor already suspected something was wrong when he found the Sixth Doctor working with the Forge, but gets further proof that something else is going on when the Sixth Doctor loses an arm (an injury the Seventh doesn’t recall ever suffering) and doesn’t show signs of regenerating.
- Beware the Nice Ones: Seven says he's not as forgiving as Six.
- Brain Washed And Crazy: Cassie
- Break the Cutie: Evelyn was already starting to crack in the previous two adventures. This one sees her completely broken emotionally.
- Buffy Speak:Evelyn: "Hunting doesn't seem very ... Time-Lordy?"The Doctor: "... Time-Lordy?
- Compelling Voice: Seven uses his again.
- Cyborg: Nimrod.
- Dirty Coward: Clone Six.
- Downer Ending: For Six.
- Dying as Yourself: Both Cassie and Clone Six.
- Elevator Floor Announcement: Seven does this. Again.
- Seven: "Ground floor, capture and certain torture!"
- Exact Time to Failure: After the Hades Protocol is activated.
- Face–Heel Turn: Cassie.
- Flatline
- Foreshadowing: The Seventh Doctor tells Nimrod that Evelyn never forgave him for Cassie's death, "even at the end."
- Artemis asks Evelyn how long the Doctor has been unaware.
- For Science!: Nimrod plans to torture the Doctor just to see how long it takes him to regenerate, and what happens during the process.
- Genetic Memory: Six clones.
- Great White Hunter: Professor Harket.
- Ground Hog Day Loop: The Kitchen is in one.
- Hassle-Free Hotwire
- Healing Factor: Nimrod has one, but he is also trying to crack the secret of regeneration.
- Heroic BSoD: Evelyn.
- Heroic Sacrifice: Cassie and Clone Six each give their lives to stop Nimrod getting the Doctor.
- I Hate Past Me: Different from The Sirens Of Time that Seven is outraged with Six's behaviour. Six is a clone.
- "I Know You Are in There Somewhere" Fight: Evelyn gives this to Cassie.
- I'm A Soldier Not A Techie
- Implacable Man: Nimrod.
- Insufferable Genius: Evelyn actually corrects the Doctor.
- Just Following Orders: The soldier working at the Forge. And Artemis.
- Killed Off for Real: Cassie.
- Medical Horror
- Meaningful Name: Project Lazarus is named after the Doctor, the man who rises from the dead.
- Mind Meld: Seven uses this to confirm that Six is a clone of himself.
- Morality Chain: Tommy to Cassie.
- My God, What Have I Done?: Cassie and Clone Six have one when they realise the extent of what Nimrod has done to them.
- Non-Answer:Evelyn: "What's so important about slime?"Harket: "Slime.. Blue slime."Evelyn: "Blue slime. I see why ''that's'' important."
- The Nose Knows
- Our Trolls Are Different
- Our Vampires Are Different
- Out-of-Character Alert: The mere fact that the Sixth Doctor is working with the Forge makes the Seventh suspicious.
- Pre-Mortem One-Liner
- Pull the Thread: Seven. Oh
Seven. - Resignations Not Accepted: It is stated more than once that people don't leave the Forge.
- The Reveal: Some time before she met the Doctor, Evelyn had a heart attack, and still suffers from a serious heart condition. She came with him because she thinks she might not have long left.
- Safely Secluded Science Center: The Forge's alpha facility, an isolated research base hidden in Dartmoor national park - built under the ruins of the original WWI base.
- The Scream: ... Poor Six.
- ... Poor Cassie
- Sequel Episode
- And to itself as well.
- Sequel Hook
- Shout-Out: Seven quotes Sherlock Holmes' The Hound of the Baskervilles.
- The Slow Path: The Doctor tried to come back 10 minutes after they last saw Cassie, but it unintentionally became several months.
- Music Small Reference Pools: Ludwig's Moonlight Sonata.
- Stealth Pun: At the very start of the story, the Doctor mocks a random hunter by impersonating Elmer Fudd. The Looney Tunes cartoons are what popularised the name "Nimrod" as an insult, after Bugs Bunny mocked Elmer Fudd with the name of the great hunter from Biblical lore.
- Strange Minds Think Alike
- Talkative Loon: Sergeant Frith thinks Seven is this.
- Take That Me: Nimrod preferred "The Doctor's old coat".
- Tear Jerker: Evelyn doesn't take Cassie's death well. At all.
- That Woman Is Dead
- Time Skip
- Title Drop
- Torture Porn: In what's starting to become a continuing theme for Six.
- Voice Changeling: The Six clone is able to imitate Seven and Nimrod perfectly.
- We Are as Mayflies: Six clones.
- What Happened to the Mouse?: What happened to Tommy? Later episodes reveal that he becomes a companion to Seven.
- You Have Outlived Your Usefulness
