"Alright, Doctor?" A gentle feminine voice rang out through the TARDIS.

"Yeah, just wondering why no-one around here has access to the time vortex. I mean, we should be in 52nd century Raxacoricofallapatorius, and I'm pretty sure they had access to time-travel,"

The Doctor hurried around the controls, flicking buttons and pulling levers, and with a sigh of apparent despair, flopped into the driver's chair.

"The TARDIS just seems dead. There isn't a sign of life anywhere in her, and she just won't seem to get started. This means we're stuck, on 52nd century Raxacoricofallapatorius and we can't get back!"

Rose appeared from the corridors leading away into the living area. She smiled at the Doctor, and before he could stop her, she ran towards the door, and disappeared outside.

"Doctor, do you know why we can't get the time vortex? Because we're in London."

"WHAT! We can't be in London, this looks just like the markets of........" The Doctor followed Rose outside. His jaw hit the floor as he realized that Rose was right. They were in 19th century London, Camden to be precise.

"Old girl, what did you do that for?" The Doctor turned to the TARDIS, "You sacrificed yourself to save us, and now we're stuck here. The last TARDIS in existence, and you gave yourself for me." A tear rolled down his cheek, and he fell to the floor in a flood of them, cursing himself for everything. Rose ran to his side, and held him in her arms, rocking the Lord of Time like a new born baby, comforting him as the last technology of his people faded, and he himself became the last thing from Gallifrey.

"Doctor, there's got to be something you can do. You can't just give up."

"You wouldn't understand, having been stuck in the parallel world all these years. They returned, my people, my glorious home world, and I had to send them back into oblivion, into the war and destruction, to save you. You and the entire planet. Otherwise Hell would be unleashed above you, and the human race would come to an end."

"Is that why you regenerated?"

" No. I took the decision to regenerate to save one man. Wilf. He deserved to live as much as the rest of you, and I can regenerate and live forever. That's why I come back to save you. And I need to stop now. I can't do anything anymore, I have no TARDIS. And sorry to tell you this, but there is no way back. We're going to have to blend in."

"But Doctor, you can't."

"Precisely, this is why I have the Chameleon Arch. It rewrites my DNA and can turn me into any life form in the Universe. But the one thing is, Rose, now the TARDIS is dead, there's only one way that I can change back.

"What's that?"

"It's said, that back in the very beginnings of time, when Earth was the first settled planet of the Time Lords, before we discovered Gallifrey, that the first Time Lord placed a ruby, The Ruby of Agrapur, in the centre of the Time Lord citadel, and that whoever finds it will be forever immortal, and would have endless regenerations. But Rose, if I do it, you must promise me one thing. Only get the ruby if I am mortally wounded. Don't find it if I fall over. Only if I die. Promise me that.

"I promise. But, Doctor, what about me?"

"I can reset your memories before I change, so that Rose Tyler doesn't exist yet, and so that we can forget our old life and I'll give you one completely different. If I change back, I'll get them back. And that's a Time Lord promise; immortal do you trust me?"

"Of course."

"Then let's go!" The Doctor jumped up, miles away from the state he was just in, and rushed back into the TARDIS, grabbing something swinging on the ceiling. He whipped out the sonic screwdriver, buzzing away at the headset, and then turned to Rose.

"Are you ready for Rose Tyler to go?" He said this with a note of uncertainty in his voice, like he wasn't sure, but Rose had to trust him.

"I'd give up forever to be with you, Doctor."

The Doctor nodded awkwardly and stepped forward, reaching out his hands to Rose's head. He closed his eyes, scrunching them in pain as he stepped through the memories of a life he was about to extinguish. Rose felt a sharp pain in her head, and then nothing, nothing but a voice calling out, and then darkness, calming cooling black.

The Doctor looked at Roses crumpled form on the TARDIS floor, and then hooked up the Chameleon Arch to his head. He closed his eyes and activated it, pain racking through his body, his skin crawling and his left heart fading away, before joining Rose in the silence of unconsciousness.