Jasmine was fidgeting restlessly, and on checking that the younger Doctor's back was turned, so she would not be scolded for neglecting her task, she sidled up to Jeff.
"Do you actually understand what we're doing?"
He gave her an apologetic, kindly smile.
"I usually find it's better to just get on with it, and hope he explains when it's all over."
She turned hopefully to Anna, and was rewarded with a dark scowl.
"I'm working with a lump hammer here. Does it look like I understand all the cosmic whosits?"
Jasmine backed off and glanced around. Her own Doctor was hard at work freeing something from the Skypig's innards, but the elder didn't look busy. She trotted up to him. His beatific look was always hard to read, but he looked pleased to have the company.
"Finished already, Jasmine?"
"Um, almost." She glanced guiltily over her shoulder. "I was hoping you might tell me a bit more about the plan."
"Well..."
"I mean, all the stuff about how we're going to destroy the universe, that's just melodrama isn't it?"
"Ah." His parchment-like face creased with the effort of suppressing a smile. "Well, yes, I suppose it is rather. But from our perspective at least it's also the literal truth. This reality is, to use a technical term, broken, and needs to be done away with. Now, when Krongeist rips open the weakened membrane of the universe so that he may escape his present limbo state he will leave a gap which, while it will eventually heal up, will for a few hours be in an appallingly fragile and vulnerable state. So when we fly our patched up Skypig directly into it, the resulting cataclysm will be so vast that it will achieve the required result. Not merely to devastate or destabilise this reality, but to annihilate it completely, so that everything that has happened here will never have occurred, and all will be as it was."
He spoke so calmly and pleasantly that it was hard for Jasmine to believe she had not misheard him. The insane, grandiose scale of the plan was impossible to reconcile with the hunched, inoffensive old man sitting in front of her.
"But... but..." She grappled to find a question that made sense when the entire plan clearly didn't. "But if everything's back the way it was, what's to stop Krongeist doing exactly the same thing all over again?"
"Excellent question," the Doctor complimented her. "But, you see, the temporal distortion caused by sending the Skypigs back in time is very localised. As an incomer, from outside its influence, you weren't affected by it and that's why you could see the changes taking places on Agrathus when the locals couldn't. Similarly, if we destroy the alternate timeline he has created, it won't change the fact that Krongeist has expended most of his reserves of power on penetrating reality to contact Temore. He won't be able to do it a second time."
Jasmine shook her head, not in disagreement but as if physically dazed and trying to clear it. It was a relief to hear brisk footsteps behind her and the younger Doctor's voice:
"Do you think you could realign the spatial orientation circuits?"
"Ah." Moving slowly, the elder laid down his stick and accepted a tangled chunk of machinery in both hands. "A nice, sedentary task. Thankyou."
The younger turned to his companion.
"Jasmine. Finished already?"
She sighed.
"No, don't start. I'm going. But..." She curled her finger to point back behind her at Jeff and Anna, keeping it hidden from them by her body, and lowered her voice: "Have I met these people before?"
The elder looked up with interest at his future self's face, but the younger scarcely blinked before replying:
"Yes, they came and visited me a few times when you were tiny."
"Ah!" Jasmine looked relieved at a puzzle solved. "I thought they looked familiar."
She trotted off, back to work, and the Doctors watched her go. The elder spoke softly.
"You're not going to tell her?"
The younger looked round sharply, then lowered himself to sit beside the old man on the tree trunk.
"I'm thinking not." He looked awkward, glancing over at Jasmine again, tense for a reply. When none came, he grudgingly looked back at the elder. "How long have you known?"
"Hmpf. It took me all of two minutes to spot the family resemblance. I must be getting senile. In my defence, the concept of Jeff and Anna choosing to spend five minutes more than necessary in one another's company seemed unlikely enough, let alone their choosing to have a child together."
The younger sighed reminiscently.
"It took time. A lot happened."
"Why doesn't she recognise them? Ah, no." The elder held up a hand as the other Doctor flinched. "She already told me she never knew them. I don't want to hear about that. I just wondered why she didn't recognise their names."
"Oh. Well, they had to adopt false names when you eventually returned them to Earth. You remember before you left there was that business with Anna punching the Queen's Equerry."
"Oh yes."
The two were silent for a moment, lips twitching at the identical memory that flashed across their minds.
"Well." The younger placed his hands on his knees decisively. "I'd better get back. Before Jeff decides to take the whole thing to bits and find out how it works."
"Are you being kind to her?"
The younger paused at the abrupt question, and slowly drew his hands away to rest them on the tree trunk by his sides.
"In my fashion."
He saw the sceptical expression on the elder's face and quickly spoke again.
"Well, we can't all be loveable old codgers, you know."
"My dear young man," the elder said, "That girl has lost her home and her family and everything she ever knew. She has nothing and no one, she belongs nowhere..."
"She belongs with me."
The quiet, serious tone of the reply gave the elder pause, but he leaned forward and spoke gently.
"Does she know that?"
The younger frowned and looked away.
"Don't lecture me," he said distantly, as if his mind were elsewhere. "I'm more than twenty years older than you."
"Then no doubt you've considered this. If Jasmine does not feel loved, if she doesn't feel the Tardis is her home, then the first time she finds someone she can care for, or a place where she can be happy, she will leave you. And you'll be left once again, spinning aimlessly through the cosmos, alone."
The younger Doctor rose to his feet and looked down contemplatively at his ancient former self.
"It's something to think about."
He walked away across the clearing, back towards the others.