This story is a crossover between Doctor Who and Sonic the Hedgehog. Just so you know, this follows Sonic's SatAM continuity. It goes as far as the last episode of that series. I have never read the Archie comics series that supposedly continues the story beyond the end of the TV show so none of that applies here – please don't send me notes saying that "Archie says this or that." Consider this very AU if you like.

Anyway Tails has always been my favorite character in the Sonic universe and in the SatAM series he was severely underused. But then along came the "Drood Henge" episode where he was pretty much running the whole show. And I thought well Tails has always been considered a genius, but maybe he had some help in his education that we never knew about, help which would also explain why he sometimes (often!) wasn't around at all for whole episodes at a time. Perhaps such help that could only come from a certain Time Lord?

And so this story was born. The framing device – of telling stories in King Maximilian's private parlor – occurs after the "Doomsday" episode. The first chapter is mostly prologue that basically wraps up the SatAM series in an AU manner and sets the stage for the rest of the saga. Otherwise, for Tails and the Freedom Fighters, the story mainly takes place late in the second season of SatAM, but before "Drood Henge." For the Doctor the story occurs during season 14 of the classic series, specifically after the "The Deadly Assassin" and before "The Face of Evil." At this time the 4th Doctor was traveling alone and we don't know exactly how long he was alone for.

With all that said and done I hope you like this crossover. Neither Doctor Who nor Sonic The Hedgehog belong to me. Doctor Who is property of the BBC. Sonic The Hedgehog SatAM is property of Sega and DIC. The only thing that's mine is the story itself. Please read and review; I always appreciate feedback. Constructive criticism is welcome; flames will be deleted. Enjoy!

1 – PROLOGUE: THE KING'S PRIVATE PARLOR

King Maximilian Acorn looked out of a window of his recently rebuilt palace. There was no denying that the rebuilding of Mobotropolis was proceeding much more quickly than anyone had dared to hope or expect following the final defeat of Dr. Robotnik and his Doomsday plan by the Freedom Fighters. Events had moved very quickly after that. It seemed it had only been a short time earlier when he himself, along with magician Ixis Naugus, had been imprisoned in the Void. But right after Robotnik's final defeat Naugus had found a way to rescue both of them from the Void without any ill effects. They had arrived back on Mobius to find the king's own daughter, Princess Sally Acorn, mopping up the last of Robotnik's forces, including Robotnik's nephew Snively who had been caught not long after and was now permanently imprisoned.

It had been just over a year since then. The king admitted that he had been most impressed by his daughter; she was no longer the young child he knew from before the coup. She was now over 17 and the years of leading the resistance had left their mark. She was mature well beyond her years and had developed into a very capable leader in her own right. She had also become a very beautiful young woman who reminded the king very much of her mother.

King Maximilian sighed to himself; he had missed so much. When he returned from the Void he found that he had so much catching up to do that he needed guidance of his own. One of his first acts was make Sally his co-regent, to rule with him. This allowed him a chance to get to know all of his daughter's comrades. It also placed Sally front and center of the kingdom's reclamation, rather than removing her from command. This was a very wise decision; it not only helped smooth over the king's own re-introduction to his realm, but it also gave continuity to the leadership between the former resistance and the rebuilding kingdom.

There was no denying that the kingdom was rebuilding faster than anyone could have foreseen. A general clean-up of pollution had occurred and houses were being reclaimed and rebuilt. A lot of the rebuilding had been sped up by the Freedom Fighter's biggest hero, Sonic the Hedgehog, who was now applying his matchless speed to help rebuild the city. With his hands (and feet), and with mechanic Rotor's plans, houses had been rebuilt, streets restored, and even work on restoring parkland and monuments had begun.

The king reflected on the young hedgehog; on the whole he liked him. He had known him first as a young boy; the nephew of one his best friends, Sir Charles Hedgehog (familiarly known as "Uncle Chuck"). When he saw him again during his first (brief) rescue from the Void he had seen the bond between Sonic and his daughter, one that he found had been strengthened upon his permanent return to Mobotropolis. They were the same age and despite their frequent arguments it was apparent to him (and almost everyone else) that they were in love. Although they were still young he wouldn't be surprised to see them married eventually. It would be a good match: with Sally as the brains of the pair and Sonic as the action part of the two they ought to make a good team. And of course Uncle Chuck, recently de-roboticized (first of many victims who were now being restored to themselves through the de-roboticizer) would be there to help.

The thought of Uncle Chuck brought King Maximilian to the main mystery he had been pondering recently. The building of the de-roboticizer had been nothing short of a miracle since for so long all attempts to reverse Robotnik's roboticizing process had failed. It had been done at last, but not by Uncle Chuck, or Rotor, or even Snively. No, the person who built the de-roboticizer was a young two-tailed fox that everyone called "Tails." The king had first met Tails after his return from the Void – he had not been born until after the Coup. No one seemed to know who his parents were; he had been found as an infant in the Great Forest and had been raised in Knothole, mainly by Sally herself, whom the young fox called "Aunt Sally," and Sonic whom he looked up to as a big brother. He was said to be 11 years old now; the king found him to be still very much a child, though a very mature one. He was also very cute and quite attached to those he considered family. When he first met Tails after returning from the Void the king had said to him "if Sally is your aunt, then I must be your grand-uncle!" The young fox had taken the King at his word and called him "Grand-Uncle Maximilian" ever since, and the king liked it.

Tails' real name, according to a note found with him when he was first discovered, was "Miles Prower" but he hated that name so Sonic had eventually dubbed him "Tails" and it stuck. That might be a clue to his origin, the king thought. There had been a general in his service before the coup who had the surname of "Prower" and he had been married. But as far as the king remembered they did not have any children at that time. They were among the many missing now. If Tails was their son the king wondered what had happened to them and why they had been forced to abandon him. It was possible no one would ever know.

Somehow this child had to turned out to be a super genius, with an intellect rivaling, maybe even exceeding, Dr. Robotnik's himself. No one knew just how smart Tails was since he was still growing up but sometimes there seemed to be no limit to his mind. He still had a child's curiosity about everything and he was constantly inventing things in his private workshop on the palace grounds. The de-roboticizer had been his biggest triumph so far.

There was more to Tails' story though; the king knew that Tails had not honed his mind all by himself. There were whispers he would sometimes hear from the Freedom Fighters about Tails; a couple of years earlier he had disappeared from Knothole for some time; when he had returned his mind was much more fully formed than anyone expected and he was soon surprising everyone with what he could do. Sally had told her father that Tails had actually left the planet in the company of an alien who called himself only "The Doctor" who came and went in a craft that seemed to just appear and disappear out of thin air. When the king pressed his daughter for more details she had smiled and simply said that he should ask Tails about it himself because it wasn't her story to tell. The king had been meaning to do this for some time but business had kept him from doing so.

Lately there seemed to be a slight in change in Tails. When the King had first met Tails the boy had been very cheerful and optimistic, even innocent despite having grown up during the war against Robotnik. He still was that way most of the time but lately a certain reserve and pensiveness had entered into his manner, as if he had something heavy on his mind that he didn't know how to resolve. Ironically it had started right after the triumphant successful testing of the deroboticizer. Looking back on it now the King was able to put his finger on that event as the moment when Tails' slight withdrawal had started and he wondered why. Sonic and Sally certainly were aware of this change but if they had spoken with Tails about it they had not said anything. Bunnie probably knew too, considering how close she and Tails were, but as far as the King could tell no else had noticed any difference in Tails' manner.

One of King Maximilian's chief pleasures since the rebuilding of his palace was to spend evenings with friends gathered around him in his private parlor to swap stories by the fireplace. In particular the king liked to gather various Freedom Fighters there and hear about their lives during the struggle against Robotnik. This was one way he learned about much that he had missed during his exile. Sally was usually at these gatherings, and Sonic with her. The other major Freedom Fighters were often in attendance too, including Rotor, Bunnie Rabbot (now having received her regular leg and arm back from the de-roboticizer), Antoine De-Coolette, the cowardly guard with a crush on the Princess (the king thought that would take care of itself eventually, especially considering how Bunnie had been looking at Antoine in the past months), Uncle Chuck often was there, Dulcy Dragon would fly in sometimes, and even Tails would be there for a while, or at least until Sally sent him off to bed.

Tonight they were all there. It was a chilly night outside and the fireplace had a roaring fire going. The king turned towards Tails. He considered the young fox thoughtfully. Perhaps tonight – ? Yes.

"I've heard a lot of things about you Tails" he said to the fox, "and I've been impressed with what I've seen you do since I've gotten to know you."

"Thank you Grand-Uncle Maximilian" said Tails a little nervously.

"You're welcome" said the king, "I'd like to hear your story tonight."

"My story?"

"Yes, well one story in particular" replied the king, "I'd like to hear about this person called 'The Doctor.' Everyone says that it's your story."

Tail smiled a little wistfully.

"Oh yes, The Doctor" said the fox, "I miss him. He took me traveling all over the place."

"So I heard" said the king, "but who was he?"

"That's a long story" said Tails.

"Unfortunately" said Sonic from his seat; the hedgehog always did have trouble sitting still for a long time.

"Now Sonic" said Sally, laying a hand on his hand. Sonic smiled at her. From his seat Antoine grimaced.

"The Doctor's an alien" said Sally, "he's not from this planet at all. But you might not know that just to look at him."

"Yeah" said Sonic, "if you just looked at him you'd think he was from the same kind of people as old 'Buttnik."

"An Overlander?" asked the king.

"No" said Tails, "he only looks like one. He's actually a Time Lord."

"What is a Time Lord?" asked the king.

"Well," said Tails, "like I said, it is a long story. I'm not sure where to start."

"Start from the beginning" said the king, "and stop to explain things if you have to."

"Okay" said the fox leaning back in his chair, "the beginning? Well it really began the day I found the large blue box in the forest outside of Knothole..."

(To Be Continued)

A/N - And... we're off! I know this chapter was rather slow and expositional, mostly prologue stuff. It'll pick up a lot in the next chapter. Thanks for reading!