You:
*sighs* Yeah I know.

Gunfire. Jenny runs back.

Jenny:
They've blasted through the beams. Time to run again. Love the running. Yeah?

You:
*smiles* Love the running.

Up on the surface, Cortana can see the protruding construction of the Temple.

Diana:
We're trapped.

You:
Can't be. This must be the Temple. This is a door.

60120712.

Diana:
And again. We're down to one two now-

You:
I've got it!

Jenny:
I can hear them.

You:
Nearly done.

Diana:
These can't be a cataloguing system.

Jenny:
They're getting closer.

You:
Then get back here.

Diana:
They're too similar. Too familiar.

Jenny:
Not yet.

You:
Now! Got it.

The Doctor gets the plain door open and they go through. A similar door opens for Cortana on the surface.

Jenny:
They're coming. Close the door.

[Spaceship]

The Doctor locks the door.

Jenny:
Oh, that was close.

You:
No fun otherwise.

DONNA:
It's not what I'd call a temple. 
JENNY:
It looks more like-

You:
Fusion drive transport. It's a spaceship.

Diana:
What, the original one? The one the first colonists arrived in?

You:
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.

They head up a flight of stairs to see someone is cutting their way through another door.
Jenny:
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.

You:
Look, look, look, look, look. Ship's log.

The screen says Messaline Leader One mission log designation XG2482942-372.

You:
*reads* First wave of Human/Hath co-colonisation of planet Messaline. 

Core subterranean deployment successful. Online and active. Phase one initiated. Construction drones deployed. Construction of sections 1A, 1B, 2A, 2B, 3C & 3D complete. Phase one in progress. Construction drones active. Construction of sections 1C, 1D, 2C, 2D, 3A & 3C complete.

Jenny:
So it is the original ship.

Diana:
What happened?

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

Diana:
But does it mention the war?

The Doctor scrolls down through Phase One in progress. Construction of western quadrant complete. Phase two initiated. Commencing colonisation protocol 0.7. Designated pioneer progenation in progress. Mission commander quarantined due to eruption of byzantine fever. Prognosis negative.

You:
Final entry. *reads* 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.

Jenny:
Two armies who are now both outside. 

Diana:
Look at that.

60120724 on a display above a screen showing the whole planet.

You:
It's like the numbers in the tunnels.

Diana:
No, no, no, no. But listen, I spent six months working as a temp in Hounslow Library, and I mastered the Dewey Decimal System in two days no time. I'm good with numbers. It's staring us in the face!

Jenny:
What is?

Diana:
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.

You:
Oh! It's the New Byzantine Calendar.

Diana:
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.

You:
Yes. Oh, good work, Diana.

Diana:
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.

You:
Oh seven twenty four. No!

Jenny:
What does it mean?

You:
Seven days.

Diana:
That's it. Seven days.

You:
Just seven days.

Jenny:
What do you mean, seven days?

You:
Seven days since war broke out.

Diana:
This war started seven days ago. Just a week. A week!

Jenny:
They said years!

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

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

Jenny:
But all the buildings, the encampments. They're in ruins.

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

Further along, they meet up with Cortana for a joyous reunion.

Cortana:
Doctor!

You:
Cortana! Oh, I should have known you wouldn't stay away from the excitement.

Cortana:
Diana. *hugs Diana*

Diana:
*hugs Cortana* Oh, you're filthy. What happened?

Cortana:
I, er, took the surface route.

Cobb:
*in the distance* Positions.

You:
That's the General. We haven't got much time.

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

Cortana:
Is it me, or can you smell flowers?

Cobb:
*off in the distance* Maintain defensive positions.

You:
Yes. Bougainvillea. I say we follow our nose.

Cobb:
*off in the distance* Squads seven to ten, advance. With me.

[Hydroponics]

You:
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.

Diana/Cortana:
Is that the Source?

Jenny:
It's beautiful.

Diana:
What is it?

You:
Terraforming. It's a third generation terraforming device. 

Cortana:
So why are we suddenly in Kew Gardens? 

Diana:
Because that's what it does. All this, only bigger. Much bigger. It's in a transit state. Producing all this must help keep it stable before they finally-

The Hath and the soldiers run in from opposite sides.

You:
Stop! Hold your fire!

Cobb:
What is this, some kind of trap?

You:
You said you wanted this war over.

Cobb:
I want this war won.

You:
You can't win. No one can. You don't even know why you're here. Your whole history, it's just Chinese whispers, getting more distorted the more it's passed on. This is the Source. This is what you're fighting over. A device to rejuvenate a planet's ecosystem. It's nothing mystical. It's from a laboratory, not some creator. It's a bubble of gases. A cocktail of stuff for accelerated evolution. Methane, hydrogen, ammonia, amino acids, proteins, nucleic acids. It's used to make barren planets habitable. Look around you. It's not for killing, it's bringing life. If you allow it, it can lift you out of these dark tunnels and into the bright, bright sunlight. No more fighting, no more killing.

The Doctor takes the globe.

You:
I'm the Doctor, and I declare this war is over. 

You throw the globe onto the floor, where it smashes and releases gas and energy. Everyone watches it slowly rise up, then they start to put down their weapons. All except Cobb.

Jenny:
What's happening?

You:
The gases will escape and trigger the terraforming process.

Jenny:
What does that mean?

You:
It means a new world.

Jenny:
No! 

Jenny takes the bullet Cobb intends for the Doctor. He lays her on the ground.

You:
Jenny? Jenny. Talk to me, Jenny. 

Diana:
Is she going to be all right? 

Cortana shakes her head.

Jenny:
A new world. It's beautiful.

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

Jenny:
That sounds good.

You/Diana:
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? Jenny? 

Jenny dies in the Doctor's arms. Or so he thought.

You:
Two hearts. Two hearts. She's like me. If we wait. If we just wait.

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

You:
No. Too much. That's the truth of it. She was too much like me.

The Doctor lays Jenny down and kisses her forehead, then goes over to Cobb. Cline and another soldier are holding his arms and making him kneel. The Doctor picks up the pistol and points it at Cobb's head for a very long time before putting the safety back on.

You:
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!

-Timeskip-

The Doctor, Diana and Cortana stay for the burial, after Cline and a Hath soldier step back and pray silently for her Jenny exhales regeneration energy and some of the energy from the terraformation energy. She sits up and gasps for air.

You and Diana run over to her and hug her tightly, never wanting to let go.

You:
Jenny?

Jenny:
Yeah dad?

You:
How would you like to travel with us?

Instead of a response she tackles you and Diana to the ground in a hug.

Jenny:
Yes!

-Timeskip-

You, Cortana, Diana, and Jenny went back to Earth and Diana still hasn't told you about a certain Spider.