A/N - I am having so much fun with this! We find out some more about Elise's backstory and our little Timelord is starting to bond with the Tenth Doctor.

They were shoved into the cell.

The Doctor and Ten started fussing over Elise and she pushed them away. "I'm fine!"

"Ow," the older Doctor muttered.

Elise looked over at him.

"I'm okay, my dear."

"Three of us in one cell? That's going to cause some nasty anomalies if we don't get out soon," Ten said.

The Doctor picked up a piece of metal off the floor and started scratching at a stone pillar.

"What are you doing?" Ten asked him.

"Getting us out."

The older Doctor tried sonicing the door.

"The sonic won't work on that, it's too primitive," Ten said.

"Doesn't do wood," Elise explained.

"Shall we ask for a better quality of door so we can escape?" the Doctor asked.

"Okay, so the Queen of England is now a Zygon. But never mind that. Why are we all together? Why are we all here? Well, me and Chinny, we were surprised. Elle has no idea who you are, but you came looking for us. You knew it was going to happen. Who told you?" Ten asked the older Doctor.

"Oi, Chinny?" the Doctor snapped.

"Yeah, you do have a chin."

Elle? The Doctor had never called her that, so why was his younger incarnation calling her that?

"In theory, I can trigger an isolated sonic shift among the molecules, and the door should disintegrate," the older Doctor said.

"We'd have to calculate the exact harmonic resonance of the entire structure down to a sub-atomic level. Even the sonic would take years," Ten explained.

"No, no, the sonic would take centuries. Oh, we might as well get started. Help to pass the timey-wimey. Do you have to talk like children? What is it that makes you so ashamed of being a grown up? Oh, the way you both look at me. What is that? I'm trying to think of a better word than dread."

"It must be really recent for you."

"Recent?"

"The Time War. The last day. The day you killed them all," the Doctor said.

"The day we killed them all," Ten corrected him.

"Same thing."

"I don't talk about it," the older Doctor told them.

"You never talk about it. I have been with you for hundreds of years and you've never once sat me down and explained what you did that day," Elise said.

"Because you don't need to know," the Doctor said.

She rounded on him. "Who says I don't need to know! I am an adult! I'm not a child anymore! Quit treating me like one!"

Ten couldn't help but smile. He'd missed her sassy personality (even when it was directed at him). It reminded him of Donna.

"I killed you. I killed the one thing that means more to me than anything in the universe. And then you died again while you were under my watch," the Doctor whispered.

"You didn't know who I was," Elise told him.

"Doesn't change the fact that I did it."

Ten turned to her. "Tell me."

"Tell you what?"

"How did you escape the Timelock?"

Elise's hearts froze in her chest. "How do you know about that?"

"It's kinda obvious."

"It's complicated."

"Ellie," her father said softly.

If there was a time to come clean, now was it.

Elise looked at the three Doctors and sighed. "My father was on the High Council, so I knew what they were planning. I heard all the discussions and the arguments about what to do. I listened to them read off the number of causalities. Civilians and soldiers alike. They didn't care. All they cared about was winning the war against the Daleks. They didn't care who lived or died. Imagine being four years old and in all that time all you knew was death, destruction, and war? My father worked long hours. When he came home, all my mother and him did was fight. So what did I do? I quit talking. Why talk when no one will listen to you anyway?"

"But how did you get out of the Timelock?" Ten asked.

Elise knew it hadn't happened for him yet, so she had to be careful what she said. "What my father didn't know was that I was clever."

"You ran?"

"I wanted off Gallifrey. I didn't care how."

"Sound familiar?" her father asked.

"Hey, if I knew what a TARDIS was, I would've stolen one of them. I was just working with what I had."

"Did you ever count?" the older Doctor asked.

"Count what?" the Doctor asked.

"How many children were on Gallifrey that day?"

"I have absolutely no idea."

"How old are you now?"

"Ah, I don't know. I lose track. Twelve hundred and something, I think, unless I'm lying. I can't remember if I'm lying about my age, that's how old I am."

"Four hundred years older than me, and in all that time you've never even wondered how many there were? You never once counted?"

"Tell me, what would be the point?"

"2.47 billion," Ten answered for him.

"You did count!" the older Doctor said, surprised.

Ten turned to his older incarnation with disgust. "You forgot? Four hundred years, is that all it takes?"

"I moved on."

"Where? Where can you be now that you can forget something like that?"

The Doctor grabbed Elise and put her between them. "Because of this girl right here. She is the reason you move on. Because she's the one you saved. After that, nothing else will ever matter again. Except her."

Ten looked down at her wide emerald eyes and stalked away.

"I don't know who you are, either of you. I haven't got the faintest idea," the older Doctor said, "No."

"No?" Ten asked.

"Just, no."

The Doctor started laughing.

"Is something funny? Did I miss a funny thing?" Ten asked him.

"Sorry. It just occurred to me. This is what I'm like when I'm alone."

Ten started tossing his screwdriver in the air and the older Doctor pulled his out.

"Four hundred years," the older Doctor muttered.

"I'm sorry?" Ten asked.

"At a software level, they're all the same device, aren't they? Same software, different case."

"Yeah."

"So...." The Doctor said, pulling out his own.

"So, it would take centuries for the screwdriver to calculate how to disintegrate the door. Scanning the door, implanting the calculation as a permanent subroutine in the software architecture and, if you really are me, with your sandshoes and your dickie bow, and that screwdriver is still mine, that calculation is still going on."

The Doctor and Ten checked their screwdrivers.

"Yeah, still going," Ten said.

"Calculation complete. Hey, four hundred years in four seconds. We may have had our differences, which is frankly odd in the circumstances, but, I tell you what, boys. We are incredibly clever," the Doctor said, smiling.

The door suddenly swung open and Clara was standing there.

Elise had never been so happy to see Clara in her life.

"How did you do that?" the Doctor asked her.

"It wasn't locked."

"Right."

"So they're both you, then, yeah?"

"Yes. You've met them before. Don't you remember?"

"A bit." Clara looked at Ten. "Nice suit."

"Thanks."

"Hang on. Three of you in one cell, and none of you thought to try the door?"

"It should have been locked," the older Doctor said.

"Yes. Exactly. Why wasn't it locked?" the Doctor asked.

The door swung open a bit more and Elizabeth stood there. "Because I was fascinated to see what you would do upon escaping. I understand you're rather fond of this world. It's time I think you saw what's going to happen to it."

Elizabeth led them deeper into the Tower dungeons.

The walls were covered in red pods.

"The Zygons lost their own world. It burnt in the first days of the Time War. A new home is required."

"So they want this one," Clara asked.

"Not yet. It's far too primitive. Zygons are used to a certain level of comfort."

A Zygon walked up to them and Elise jumped back into her father and Ten. They both put a comforting hand on her shoulder. She'd never seen one before, so it was quite off-putting.

"Commander, why are these creatures here?" the Zygon asked.

"Because I say they should be. It is time you too were translated. Observe this. I believe you will find it fascinating."

The Zygon placed it's hand on a glass cube and disappeared into the painting they saw earlier in the Under Gallery.

"That's him! That's the Zygon in the picture now," Clara said.

"It's not a picture, it's a stasis cube. Time Lord art. Frozen instants in time, bigger on the inside, but could be deployed as..." the older Doctor started.

"Suspended animation. Oh, that's very good. The Zygons all pop inside the pictures, wait a few centuries till the planet's a bit more interesting, and then out they come," Ten finished.

"You see, Clara, they're stored in the paintings in the Under Gallery, like cup-a-soups. Except you add time, if you can picture that. Nobody could picture that. Forget I said cup-a-soups," the Doctor said.

"And now the world is worth conquering. So the Zygons are invading the future from the past," Clara surmised.

"Exactly."

"And do you know why I know that you're a fake? Because you're such a bad copy. It's not just the smell, or the unconvincing hair, or the atrocious teeth, or the eyes just a bit too close together, or the breath that could stun a horse. It's because my Elizabeth, the real Elizabeth, would never be stupid enough to reveal her own plan. Honestly, why would you do that?" Ten asked as Elizabeth narrowed her eyes at him.

"Because it's not my plan. And I am the real Elizabeth," Elizabeth said.

"Smooth, Casanova," Elise muttered.

"Yeah, shut-up. Okay. So, backtracking a moment just to lend context to my earlier remarks," Ten said.

"My twin is dead in the forest. I am accustomed to taking precautions," Elizabeth told him. She pulled out a dagger from underneath her skirts.

"That's familiar," Ten said, looking at Elise.

"These Zygon creatures never even considered that it was me who survived rather than their own commander. The arrogance that typifies their kind," Elizabeth explained.

"Zygons?" Clara asked.

"Men."

Elise snorted in amusement and then turned to her father. "You just love strong women don't you?"

"Oh, shut-up."

"And you actually killed one of them?" Clara asked.

"I may have the body of a weak and feeble woman, but at the time, so did the Zygon. The future of my kingdom is imperiled," Elizabeth said, "Doctor, can I rely on your service?"

"Well, I'm going to need my TARDIS," Ten told her.

"It has been procured already."

"Ah."

"But first, my love, you have a promise to keep."