"Doctor, who were those people?"

The Doctor pressed his lips together, holding back a sigh. 'Rule one,' he thought, 'the Doctor lies…' "Just some old friends, Leela. Other Time Lords."

"The one in black is a warrior," she observed.

"What makes you say that?" he asked carefully, respecting Leela's instincts in such matters.

"His eyes…they've seen too many battles."

The Doctor couldn't fathom what circumstance could change him so drastically, and he also knew that he really shouldn't pursue the matter too deeply. Distraction…he needed a distraction…

"I didn't know that your people had warriors. And the funny one…why did his TARDIS look just like yours on the outside, but different inside?"

"Well, as I said, it's his TARDIS, he can decorate it any way he likes."

"And what did he mean when he said it was good to see us again?"

"He meant just what he said."

"But, Doctor…"

"Why don't you run along and fetch your bow and arrows? We're nearly to Serengeti Twelve."

"Doctor, who were those people?"

The Doctor huffed out an irritated breath. He suspected that this very same conversation was taking place on three different TARDISes, scattered throughout time and space. He supposed he should just be grateful that he wasn't the one trying to find a way around explaining it to Leela. He knew - absolutely knew - that he shouldn't ponder the day's events too closely, but something in his soul shrank back from the knowledge that Rose wouldn't always be with him, and he found the future Doctor's words foreboding.

"Doctor?"

He smiled down at the bright, young face beside him, a genuine smile that only she could coax from him and held out his hand. Rose took it instantly, the way she always did. Giving in to impulse, he leaned down and kissed her forehead.

"Come here," he said, leading her to the jump seat. "Rose…" he trailed off, not entirely sure how to begin. "Those people we saw today…we were stuck in some sort of temporal anomaly…we should never have been able to all be together at the same time."

"I don't understand."

"Rose, the only way to make you understand is to tell you something about me, about my people. It's something you should know, so you won't be frightened if I -"

His explanation was abruptly cut off as the console room seemed to tilt on its axis and alert klaxons started to blare. It was all he could do to hold on to Rose as they were tossed violently to the floor. It would be quite some time before he recalled that they'd never finished this conversation, and by that time, it was far too late.

"Doctor, who were those people?"

He'd been expecting the question all day. He supposed he actually had the easiest job of the three of them…no need to worry about mucking up his own future before it could happen. He sighed as he sank down to sit on the steps. "Come here, Clara," he invited, holding out his hand.

She took it and sat down beside him.

"Clara, that man you met, in the black leather jacket…he was me."

"That doesn't make any sense."

"I know…I know," he gripped her hand tightly in both his own. "Just…just listen, and I'll try to explain. We were caught in some sort of -"

"Anomaly," she finished the sentence for him.

"Anomaly," he agreed, smiling just a bit. "Three different versions of myself were in one place. That should be impossible, except that well…it happened."

"What do you mean, different versions of yourself?"

"Clara, I'm over nine hundred years old, but I've only looked like this for just the last few. A while ago, I wore that black leather jacket, and those unfortunately large ears, and traveled with a girl named Rose."

"I liked her," Clara interjected.

"So did I," the Doctor replied with a sigh. "And quite a long time before that, I looked altogether different and traveled with someone called Leela."

"The cave girl? The one with the knife?"

"That's right," he chuckled.

"But how is that possible?"

"It's a gift of my people. When our bodies become injured to the point of death, we can regenerate. Our bodies heal themselves…but even more than that…we change…look different, sound different…"

Clara swallowed hard trying to process the information. "What about your memories? I mean, if you were to change right now…would you remember me?"

He turned and took her face firmly in both his hands. "Clara Oswald, in all my life, all those centuries, I've never once forgotten anyone who's traveled with me. I remember each and every time I had to convince Leela that her knife wasn't the best solution to every problem, and every time I had to pick up Rose's jacket off the deck, and so much more…and I could never, ever forget you." He stared into her lovely brown eyes, hoping so desperately that she would understand…believe in him.

Clara reached out tentatively and placed her hands on his chest, feeling the steady beat of both his hearts. Two hearts…nine centuries of life…and all the wonderful, amazing things he'd shown her. There was never really any question. She looked up at him and smiled. "Never ever?"

She slipped both arms around his waist and hugged him tightly. The Doctor sighed in relief and kissed the top of her head.

"Anything else you'd like to share, Doctor?"