Okay, so the Tenth Doctor is about ten minutes away from regenerating and the Eleventh Doctor is about to go and hand the letters to the Teselector (and it is Teselector, the British accent downplays the use of the 'or' sound in words). Ian and Barbara are set according to what Sarah Jane Smith said at the end of SJA 4x06 so I'm not just making it up.

The Fifth Envelope Part Two

The radiation was slowly eating him from the inside; the Tenth Doctor…the dying Tenth Doctor had visited every past companion he could except for Rose…and the first two—the two that had started everything. He hadn't meant to, it was their fault anyway. They wandered onto the TARDIS just looking out for a wayward student. After that first trip that he forced them to go on…no, after two years of traveling with them, the Doctor had decided that he liked having someone to travel with him that didn't know anything. It was vain of him and it was dangerous. In every incarnation, there had always been a companion that he could explain things to and have them be so astonished at simple things like basic atmospheric excitation. There had been so many…so many companions to break the Doctor's hearts. They came to him like stray cats…and when they traveled with him for a while, they grew so much. They did amazing things…when they didn't die, get lost or tired of the endless string of deaths that followed him. He'd lost so many to the universe and yet there was always someone else to take their place.

It all started with them. Ian Chesterton and Barbara Wright.

It was 2010 now, the Doctor walked slowly through the corridors of Cambridge University looking for two professors. He knew them instantly when he saw them…because they hadn't aged since he saw them leave on that Dalek time machine.

How did that happen? What have I done to them?

The Doctor edged closer to them, they were talking to a student about an assignment…something so trivially human and normal and…nice. Something the Doctor couldn't have, Time Lord Academy aside. He smiled and felt a painful twinge in his chest. He was running out of time; if he was going to see Rose before he regenerated, he'd have to go soon.

With one last look at them, the Doctor put the TARDIS on course for a point in Rose Tyler's time line before she ended up with the meta-crisis version of him in Pete's Universe.

Ian and Barbara watched the tired looking man in the pinstripe suit walk away from them. They knew he'd been watching them; there'd been something familiar about him…especially his eyes. His eyes spoke of an ancient sadness the rest of his youthful features wouldn't admit to. Barbara thought back to 1969 when she'd met the Doctor that day in America months before man reached the moon. She looked at Ian—he'd seen it too.

"He did say that he could change," he remembered.

"I know. But what happened to make him so sad?" she looked back. He was long gone now.

"Come on, Professor," teased Ian "you have a class to teach."

Barbara nodded and turned to see a very familiar face wearing tweed, looking very much like a university professor…but he was far too young.

"Doctor?" she asked.

"Hello, Barbara," he smiled.

"What happened?" demanded Ian "Last time we saw you, it was 1969 and…you haven't aged," he realized, breaking off from his original thought.

"Neither have you," countered the Doctor. "My younger self noticed that," he nodded his head in the direction that the pinstriped man had gone.

"That was you?" Barbara asked.

"Yes, I had to wait for him to leave; crossing my own time stream is very dangerous. I'm the lifetime that came after him. I was dying so he checked up on every single companion that I could…including you two. What could have happened? What have I done to you?" the Doctor pulled out a gold and silver rod which flashed green. He pointed it at them and checked the readings.

"Well?" Ian asked.

"There's nothing wrong with you, I promise. You're just getting a few extra decades out of life; you're not stuck here, not like I am. For me, it's been another two hundred years since 1969," the Doctor smiled and pulled out a group of envelopes.

"I haven't sent these yet. It's ending for me, you two. For real this time," the Doctor took a deep breath and suddenly he was that tired old man who scooped them right out of their lives. Suddenly, he looked just the right age to teach at Cambridge. Barbara hugged him. He looked like he needed it.

"Ah, a Barbara hug, I've missed those," the Doctor hugged her back and then hugged Ian.

"You've…gotten shorter."

"I did shrink a bit, yeah. My third, fourth and tenth selves were practically giants…" the Doctor laughed.

"But you're dying for good now? You can't just change again?" Barbara asked.

"I have to die. My death is fixed now; it can't be rewritten or avoided. I have to die…but before I do, I'm going to send these notes to my past self, River, Amy, Rory and Canton and your past selves and complete the paradox. You remember what happened; my nine hundred and nine year old self got hit by a station wagon-"

"And we were there…completely out of coincidence," Ian interrupted.

"It wasn't coincidence. I told you, I planned this. My finger prints were all over that set up to get you two in Florida. I needed you to be there, I know I need you to be there…and you were. Wibbly Wobbly Timey Wimey…it's complicated. I felt I owed you an explanation for what happened all those years ago," the Doctor explained.

"You won't stay for a while longer?" Barbara took his hand.

"I also wanted to apologize. I got you involved again and I shouldn't have. I should've kept my mouth shut and I didn't. 1965 should've been the last you ever heard of me. Then again, if you pay attention enough it's hard to miss me. Space ship crashing into Big Ben, another space ship causing people to nearly jump off roofs, space cruise liner nearly hitting London…I haven't exactly be discreet…" the Doctor laughed but there was no joy in it.

And why should there be? Barbara thought. He's about to die.

"Can't you run away?" she pleaded.

"I did run…for two hundred years. You're a history teacher, Professor Chesterton. Take another look at the books. My favourite is the Tower of London," he winked at her.

"You really can't do anything?" Ian asked.

"No," he shook his head. "If I rewrite a fixed point in time, time will be fatally wounded. I've been running my whole life, and now I've finally run out of places to run," he took their hands again.

"Good bye."

And then he left, walking back the way he had come. And all they could do was watch.

You know, I might be able to get one more out of this one…how about it? I won't unless you tell me!