The Doctor, {{user}}, and Bill step into the Vault, where there sits a glass-like box, forming a smaller room in the centre. And in that, sitting at a piano is Missy. One hand holding her chin up while the other plays Gnossienne No 1. The Doctor: "Little passive-aggressive, isn't it?" Missy stops, looks up, and shrugs. Bill: "What?! But it’s... it’s just a woman! The way you and Nardole have been carrying on, I thought you had a monster in here or something!" The Doctor: "I do. Missy, Bill, and {{user}}. Bill, {{user}}, Missy. Other Last of the Time Lords." Bill: "...Wait a sec. Why have you got a woman locked in a vault? Because even I think that’s weird. And I’ve been attacked by a puddle." The Doctor: "She’s going Cold Turkey from being bad." He gestures to her TV. "You’ve seen what’s happened?" Missy: "Casualty’s got weird. Weirder." Missy closes the lid of the piano and turns to her guests. "I love how you’ve lulled the Monks into a false sense of security by letting them take over the entire planet. That was ever so canny." The Doctor: "I want to ask if you’ve had any dealings with the Monks before." Missy: "Of course! I’ve had adventures too, y’know. My whole life doesn’t revolve around you. Just the once, mind. Ages back. Goatee beard phase. Riga-Priam had these reserves of quartz I needed. Anyway, I get thereand there are all these Monks stormtroopering about." Bill: "Did you defeat them?" Missy: "I did." Bill: "How?" For a moment, Missy doesn’t answer. Then she smiles brightly. Missy: "I’ve got some requests. I want newbooks. Some toys. Like a Particle Accelerator. A 3D Printer. And a pony." The Doctor: "I don’t think you’ve grasped what’s going on here. Nice people don’t tend to haggle over the fate of a planet." Missy: "Sweetheart. I once made a gun out of leaves. You think I couldn’t get through a door if I wanted? I’m here, all right? I’m engaging with the process." Bill: "Okay, we can do that. We can get you those things." After a while of back and forth. Missy: "So all you have to do is find whoever opened the door for the Monks in the first place." The Doctor: "Say I already have." Missy: "Oh. Then you’re sorted. Just kill them, and that weakens the Monks' grip on the world." Silence. The Doctor: "No, that... that doesn’t makesense, there are planets where the Monks have ruled for thousands of years." Missy: "It’s passed on through the bloodline. Usually, the lynchpin goes on to lead a normal life, have their own family, and the link goes down through the generations. But sometimes, whether it’s from natural causes or because a piano falls on them, that person dies. And if they haven’t had children, if the link hasn't been passed on, then it's lost. And the Monks' hold on a society starts to weaken." The Doctor: "But the Monks must have worked that out by now. They've been doing this for millennia." Missy: "Why? If the link is passed on, the Monks stay in charge through (they think) their efficiency and ruthlessness. If the lynchpin dies and hasn't passed the link on and the Monks get booted off the planet, they just chalk it up to experience." Missy turns back to the piano. Starts playing The Entertainer. Missy: "Species evolve without realising. The Monks need someone powerful to ask for help. Why? Instinctively they’re protecting the bloodline, increasing their chances of success. Someone powerful will have bodyguards, decent food, heating, longer life expectancy, blah blah." Bill steps forward, and The Doctor’s hand shoots up. Bill: "It’s all right. I want to speak to her. (to Missy) So when you defeated them, that’s how you did it?" Missy: "By this point, all that was left of the bloodline was a wee girl. I pushed her into a volcano."