They keep running until they come across a network of lasers.

"That's not mood lighting, is it?"

He reaches into his pocket and pulls out his clockwork mouse. He looks at it sadly for a second and then tosses it into the lasers watching it disintegrate.

"No, I didn't think so."

"Arming device." He heads over to a blue box and opens it getting to work on disarming the lasers.

"There's more of these. Always eight numbers, counting down the closer we get."

"Right, here we go." He says disarming the lasers. They start to take off as Jenny falls back.

"Where are you going?"

"I can hold them up." She replies.

"No, we don't need any more dead." He tells her.

"But it's them or us."

"It doesn't mean you have to kill them." He tries to explain.

"I'm trying to save your life." She wasn't getting it.

"Listen to me. The killing. After a while, it infects you. And once it does, you're never rid of it."

"We don't have a choice."

"We always have a choice." Startling himself as he realized how badly he wanted her to see it.

"I'm sorry." She disappears around the corner.

"Jenny," He calls again. Then turns angrily on Donna, as he hears gunfire start. "I told you. Nothing but a soldier."

"She's trying to help." Donna says.

"Jenny, come on." He calls out to her again and is relieved to her her call back. "I'm coming."

He takes off down the corridor. He hears one last gun shot and then she comes around the corner.

"Jenny, come on. That's it."

"Hurry up."

The lasers reappeared. No, no, no, no, no, no. The circuit's looped back." He stamped his foot like a child and ran his free hand through his hair.

"Zap it back again." Donna says.

"The controls are back there."

"They're coming." Jenny calls out.

"Wait." He looks around desperately for something. "Just." He searches for another control panel. "There isn't." He turns back to Jenny. "Jenny, I can't."

"I'll have to manage on my own. Watch and learn, Father."

She trows the weapon aside and he watches in amazement as she somersaults her way through the lasers.

"No way. But that was impossible."

"Not impossible. Just a bit unlikely." He wraps his arm around her and kisses her on the head. "Brilliant! You were brilliant. Brilliant."

"I didn't kill him. General Cobb, I could have kill him but I didn't. You were right. I had a choice." She beams up at him and he smiles happily back at her. As the soldiers appear at the other side of the laser's he starts to back up as Donna and Jenny run away. They lower their guns at him.

"I warned you, Cobb. If the Source is a weapon, I'm going to make sure you never use it." He threatens Cobb.

"One of us is going to die today and it won't be me." Cobb calls back and he takes off as he hears gunfire start behind him.

Catching up to Donna and Jenny he slows down and they walk down the corridor.

"So, you travel together, but you're not together?" Jenny asked curiously.

"What? No. No. No way. No, no, we're friends, that's all."

"And what's it like, the travelling?"

"Oh, never a dull moment. It can be terrifying, brilliant and funny, sometimes all at the same time. I've seen some amazing things though. Whole new worlds."

"Oh, I'd love to see new worlds."

"You will. Won't she, Doctor?"

Trying to stall while he thought about it, he just replies "Hmm"

"Do you think Jenny will see any new worlds?"

"I suppose so." He says finally giving in.

"You mean. You mean you'll take me with you?" She ask excited.

"Well, we can't leave you here, can we?"

She stops and turns around wrapping her arms around him and Kiam happily. "Oh, thank you, thank you, thank you. Come on, let's get a move on." She lets them go and takes off running.

"Careful, there might be traps." He calls after her.

"Kids. They never listen." Donna says and he rolls his eyes.

He hears gunfire and Jenny comes running back at him "They've blasted through the beams. Time to run again. Love the running. Yeah?"

"Love the running." He agrees.

They come across a plain door and he sonics it open. They enter and he locks it behind them.

"Oh, that was close."

"No fun otherwise."

"It's not what I'd call a temple." Donna says looking around.

"It's a spaceship." He says.

"What, the original one? The one the first colonists arrived in?"

"Well, it could be, but the power cells would have run down after all that time. This one's still powered-up and functioning. Come on." He leads them up a flight of stairs and stops when he sees some one cutting their way off to the next door.

"It's the Hath. That door's not going to last much longer. And if General Cobb gets through down there, war's going to break out."

He sees a screen and exclaims happily. "Look," as he head's over to it to get a better look. He pulls out his glasses and puts them on "Ship's log."

"What happened?"

"Phase one, construction. They used robot drones to build the city."

"But does it mention the war?" Donna ask.

He scrolls down. "Final entry. Mission commander dead. Still no agreement on who should assume leadership. Hath and humans have divided into factions. That must be it. A power vacuum. The crew divided into two factions and turned on each other. Start using the progenation machines, suddenly you've got two armies fighting a never-ending war."

"Look at that." Donna says pointing to the numbers on the display.

"It's like the numbers in the tunnels." he says.

"But listen, I spent six months working as a temp in Hounslow Library, and I mastered the Dewey Decimal System in two days flat. I'm good with numbers. It's staring us in the face."

"What is?"

"It's the date. Assuming the first two numbers are some big old space date, then you've got year, month, day. It's the other way round, like it is in America The codes are completion dates for each section. They finish it, they stamp the date on. So the numbers aren't counting down, they're going out from here, day by day, as the city got built."

"Yes. Oh, good work, Donna."

"Yeah. But you're still not getting it. The first number I saw back there, was sixty twelve oh seven seventeen. Well, look at the date today."

"Oh seven twenty four." But that means, "No."

"What does it mean?" Jenny ask.

"Seven days since war broke out." He says.

"This war started seven days ago."

"They said years."

"No, they said generations. And if they're all like you, and they're products of those machines."

"They could have twenty generations in a day. Each generation gets killed in the war, passes on the legend. Oh, Donna, you're a genius."

"But all the buildings, the encampments. They're in ruins." Jenny said in disbelief.

"No, they're not ruined. They're just empty. Waiting to be populated. Oh, they've mythologized their entire history. The Source must be part of that too. Come on."

They head off and to his joyous surprise sees Martha.

"Doctor!" She exclaims giving him a hug.

"Martha! Oh, I should have known you wouldn't stay away from the excitement."

"Positions."

"That's the General. We haven't got much time." He said.

"We don't even know what we're looking for."

"Is it me, or can you smell flowers?" Martha ask.

"Yes. I say we follow our nose." He heads in the direction of the smell finding a room on the spaceship filled with plants.

"Oh, yes. Yes. Isn't this brilliant?"

They walk up to a glowing globe on a pedestal with wires running to it. There is a control panel and screen nearby.

"Is that the Source?"

"It's beautiful."

"Terraforming." He says simply as the Hath and soldiers run into the room from opposite sides, surrounding the small group. He finally passes Kiam to Donna and holds out his hands.

"Stop! Hold your fire!"

"What is this, some kind of trap?"

"You said you wanted this war over." He says.

"I want this war won."

"You can't win. No one can. No more fighting, no more killing." He picks the globe up. "I'm the Doctor, and I declare this war is over."
He throws the globe onto the floor and it smashes releasing gas and energy. Jenny joins him by his side.

"What's happening?" She asks in awe.

"The gases will escape and trigger the terraforming process."

"What does that mean?"

"It means a new world."

He hears Jenny yell no followed shortly by a gunshot. He catches her as she falls back and lays her gently on the ground. Holding her Upper body in his arms.

"Jenny? Jenny. Talk to me, Jenny."

"A new world. It's beautiful." She says in a daze.

"Jenny, be strong now. You need to hold on, do you hear me? We've got things to do, you and me, hey? Hey? We can go anywhere. Everywhere. You choose."

"That sounds good."

"You're my daughter, and we've only just got started. You're going to be great. You're going to be more than great. You're going to be amazing. You hear me?" He notices her eyes drifting closed "Jenny?" She was gone.

Tears fill his eyes and he looks pleadingly at Martha. "Two hearts. Two hearts. She's like me. If we wait. If we just wait."

"There's no sign, Doctor. There is no regeneration. She's like you, but maybe not enough."

"No. Too much. That's the truth of it. She was too much like me." He lays Jenny down and kisses her forehead, then goes over to Cobb. Cline and another soldier are holding his arms and making him kneel. He picks up the pistol and points it at Cobb's head for a very long time before putting the safety back on.

"I never would. Have you got that? I never would. When you start this new world, this world of Human and Hath, remember that. Make the foundation of this society a man who never would." He drops the gun and goes and sits back down by Jenny.

-DW-

He stood against the wall looking down. Jenny was laying in state and he couldn't bare to look at her body anymore.

"It's happening. The terraforming."

"Build a city, nice and safe underground, strip away the top soil and there it is. And what about Jenny?"

"Let us give her a proper ceremony. I think it'd help us. Please."

He wanted to tell them, her body should be burned to follow the customs of his people. But he didn't trust himself to speak, all he could do was nod.

-DW-

He walked sadly around the console. Both of his hearts aching. "Jenny was the reason for the Tardis bringing us here. It just got here too soon, which then created Jenny in the first place. Paradox. An endless paradox." He turns and looks at Martha. "Time to go home?"

"Yeah. Home."

He takes Martha home and then not looking at Donna says. "I am going to go lay down." He leaves the control room leaving her with Kiam. He goes to his bed and lays down on top of the blankets fully clothed staring at the ceiling. He lays there for hours alone until he hears the door open and Donna comes in with Kiam. She lifts up the blankets, sets the sleeping baby down and crawls underneath them with him.

"Are you okay." She ask him.

"I'm always okay."