They look out into a beautiful, calm city. Like London but a little different. "A world of peace. They're calling this the Golden Age." Who's the President? "A woman called Harriet Jones," says Pete, and the Doctor goes: Hoo. "I'd keep an eye on her." (But I would think that the fact she didn't just airlock all five million of the Cybermen means she's better -- worse? -- than the one we had here.) Pete calls the Golden Age a lie. It always is. "Temperatures have risen by two degrees in the past six months. The ice caps are melting. They're saying all this is gonna be flooded." They both know it's not just global warming: "It's the breach." The Doctor is like, "Exactly, that's what I'm saying." Travel between parallel worlds is impossible -- until the Dalek broke down the walls. Pete asks about that, but the Doctor keeps talking: "Then the Cybermen traveled across, then you lot...Every time you jump from one reality to another, you rip a hole in the universe. This planet is starting to boil. Keep going and both worlds will fall into the Void." Pete assumes that "the famous Doctor" can stop this, and seal the breach. The Doctor notes that this leaves five million Cybermen stranded on his Earth. "That's your problem," says Pete. "I'm protecting this world, and this world only." Peter's World. The Doctor chuckles and looks at him softly: "Hm. Pete Tyler...I knew you when you were dead. Now here you are, fighting the fight. Alone. ...There is a chance, back on my world, Jackie Tyler might still be alive." Pete's World: "My wife died." The Doctor notes that, coincidentally, her husband died too: "Good match." Pete ignores the Doctor, and basically starts begging for help. "What?" asks the Doctor. "Close the breach? Stop the Cybermen? Defeat the Daleks? Do you believe I can do that?" Pete is all confidence, realities, facts: "Yes." And the Doctor muses, before rushing off: "Maybe that's all I need. Off we go, then!" He grins.