(This is NOT to be confused with the fic of a similar title, "Sonic Gate". )

NOTE: I updated a small detail that I just realized was wrong. Littlefield was just a kid in 1925! Duh me!

Rated T for Teen.

As the title says, this is a crossover fic between the Sonic and Stargate franchises. In the Sonic series, it takes place inbetween Sonic Rivals 2 and the upcoming Sonic RPG; Sonic Chronicles: The Dark Brotherhood. In the Stargate world, during Atlantis, Season 4. In SG-1 time, that would be inbetween the series finale and the upcoming SG-1 movie, Ark of Truth.

EXTENSIVE KNOLEDGE OF THE STARGATE "UNIVERSE", INCLUDING ALL RACES FROM SG-1/ATLANTIS, AND THEIR TECHNOLOGY, IS REQUIRED TO FULLY UNDERSTAND THIS FIC. However, a quick crash course on Wikipedia should suffice.

Note: There are two pictures here that have Stargate Addresses on them. You'll have to copy and paste the imageshack links to see the addresses. Also, If I put the wrong third Glyph (the normal first in Earth's address) please let me know, I can never remember which one it is, as the two symbols are right next to each other on a DHD.

Now, I am proud to present

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Chapter One – Departure

The houses were quiet, considering that is was 11 PM on a Sunday; everyone was resting for the new week, and the chores of it. However, quiet didn't mean that things weren't happening, and everyone didn't mean everyone. There was one house whose façade was full of deceit; its sole inhabitant was far from sleep. He was tall, muscular, and handsome; the last person you'd suspect to be the smartest person around. He knew things others didn't. Like about the Stargate, for example.

He had always been interested in Egyptian Culture; even at thirteen, he had been allowed to go on trips to places where normal thirteen year olds could only dream about; Cairo, the Pyramids, and other places. However, he was most fascinated by the finds of a certian Professor Langford, from 1925, and, moreover, the "anomaly". Once, when he had checked the logs of the finds for a research project, the total listed weight was 563.02 Lb. However, copies of the logs of the ship that took the artifacts to the US stated that over 2500 Lb of artifacts was placed in the ship. This had sparked curiosity in him; what could account for the anomalous ton? Wondering thru database after database, and after a little harmless hacking into the Chairman of the Joint Chiefs of Staff's computer via an untraceable remote connection, and he had learned the basic information about the Stargate Program, and about the Stargate itself. Once he had established the gate's location, he set up a fake gate operator account in the Cheyenne Mountain Computer System, allowing him full access to everything to do with the Program.

It had been two years since then, and he now knew more about the Stargate and the Ancients than anyone else alive. He had been easily able fake himself government credentials giving him physical access to Cheyenne Mountain, his age unquestioned by anyone, as he looked like he was in his 20's. He had snuck to Atlantis using a cloak taken by him from Area 51. With the ATA Gene, he had also been able to fully access the Atlantis OS, and learn more than anyone else about the Stargate and the Ancients. One of these things was the method of traveling to alternate realities not accessible via a Quantum Mirror; only via a Stargate's ninth chevron.

Apparently, the Ancient's had decided to place Stargates on certain realities instead of Quantum Mirrors. Why, he did not know, but he assumed for two reasons; one, the realities could have advanced life different from normal, and the massive power requirements, the equivalent of three fully charged Zero Point Modules, would deter travel to them. And two, to protect a device that appeared so frequently in the data about the ninth chevron and the realities that he assumed it was a big deal; roughly translated, the "Inferred Ideas". According to the data, it was a device that took information about one culture and used a subspace link to transfer those ideas to other devices, where they were subconsciously transferred to the minds of that planet/realities' people. It was ingenious, and also explained a lot; it showed that some, if not all, of the "ideas" of other races of people in the universe were potentially based on actual races. It was then that he began to get involved with what he called Project SG: SonicGate; an attempt to travel to the reality of the video game character Sonic, and his friends. He had realized that the ideas of Sonic may have come to someone via the Ancient's device, and if so, then Sonic's world existed.

The first hurtle he encountered was the address to Sonic's world, designated by him as AR1-001. Without it, he had no hope of getting there. However, the Ancient database held a massive index of alternate reality addresses, and, after feeding the computer enough data about AR1-001 and that reality overall, he had an address that he calculated had a 75.3 chance of being the one he needed. The address (http://img183.imageshack.us/img183/8620/etoseoq4.jpg) was ingenious; it was Earth's address, with the first two glyphs acting as the location of the alternate reality, meaning he would end up on another version of Earth. The return address back to this Earth (http://img183.imageshack.us/img183/9910/setoebq7.jpg), was easy to find; it was the first one on the list.

The next hurdle was the power requirements. Nine chevron dialing, unfortunately, required three fully charged ZPM's in order to work, and the Gate needed so much power that the ZPM's automatically burned out once the Gate shut down. However, he had happened to stumble upon something remarkable in the Ancient Database; a planet with an Ancient complex full of ZPM's. He had taken twelve back with him; three for the dial-out, three for a dial-back, and the rest for power for the equipment he was taking with him.

The final hurdle he faced was blending in. If he was going to be able to help Sonic and his friends, it could not be as a human. He realized, therefore, he would have to rewrite his own DNA; he would have to turn into a hedgehog, like Sonic. This is what gave him the most trouble, as genetic tampering is by no means an easy science. He needed two things; the base DNA of a hedgehog, aka Sonic, and an Ancient Genetic Manipulator. The latter was easy to find, as the local Milky Way system had several planets that had them, and one or two invisible trips with SG teams to other planets, where he then left to the Manipulator, were easy to pull off. The former, however, turned out to be harder than he thought. It turned out that he needed three base DNA sequences to combine with his own in order for him to be able to manipulate his DNA to the extent of massive mutation of his body into that of a hedgehog. The three obvious candidates were Sonic, Shadow, and Silver, but how could he obtain their DNA when they were in a completely different reality? It was simple, really. The "Inferred Ideas", he learned, also had a second function; making a note of each individual's DNA as it collected ideas about them, presumably so the Ancients could study individuals of a race on a genetic level. Either way, after hours of searching the Database, he came across what he was looking for; the DNA profiles of three human-like creatures from an alternate reality called Terra Duors. When he scanned the DNA, one had genes for incredible stamina, another had DNA that was complete nonsense to him, which he assumed was Shadow's Black Arm's DNA, and the third profile had genes that he linked to telekinetic abilities. He had their DNA, and was in business.

However, even he knew that he could not change until he was thru the Stargate. So, in order to buy himself time to prepare everything, he locked out the mutations with a time delay; it would take a month before the rewriting of his DNA began.

And now, on the month to the day that he had used the Manipulator on himself, he was ready. All of the things he was taking with him, minus his laptop, which he needed, were safely locked inside of a MALP he was taking with him. He had uploaded the new dialing program to the SGC's computer mainframe last week, and the three required ZPM's were ready to be hooked up, hidden away in a janitor's closet. He walked quickly thru his home; it was empty, save for furniture and three boxes containing his research he was leaving for Colonel Carter and Dr. McKay, who was visiting Earth at the moment. He wanted to leave them all of his research, minus, of course, the address to AR1-001, which he had subsequently wiped out of the Ancient Database using Dr. McKay's access code. He had also wiped out all of the DNA patterns from AR1-001. "McKay really needs to stop mumbling his access code in his sleep." he thought.

He walked briskly out of the house, locking it as he went, walking to a waiting SUV outside. He jumped in, turned it on, buckled up, and checked the time. It was 11:05; he had until midnight to get thru the Gate before his DNA was rewritten. He backed out and drove quickly, until he reached the road that led up to Cheyenne Mountain. At 11:18, he arrived. He presented his badge to the officer at the main gate, and was saluted thru. He drove into the complex, parked his car, grabbed his bag containing his laptop, and walked over to the guard station. He placed his hand on the scanner, and it turned green; the officer saluted him thru. He walked quickly, arriving at the elevator. He opened it with his clearance card, and stepped inside, selecting Level B6, where the Stargate was held. Once the elevator stopped, he quickly walked to the MALP room, opening it with Gen. Laundry's ID card that he had nicked last week. He walked over to a particular MALP which held all of his equipment, opening his laptop and immediately calling up the Base's computer system as he did. He quickly sealed off the MALP room door he had come thru, as well as the primary door off of the nearby corridor, leaving only the door out to the Gate Room. He also sealed off the Control Room from the Gate Room, to prevent any surprises. He then walked over to the nearby computer terminal, logged on as Dr. Jackson, and called up the new dialing program. He quickly entered the address, at the same time as masking the glyphs to prevent anyone following him. He set the gate to a delayed five-minute dialing sequence, and left it at that. He then walked over to his laptop and called up the ZPM screen. He paused, as the ZPM's connection to the Gate and the power surge that accompanied it would immediately alert the Control Room to his presence. He checked his watch, 11:45, and pressed enter.

At that exact moment, Colonel Samantha Carter and Dr. Rodney McKay were in the control room looking at two anomalous deletion points in the Atlantis system command logs. They had returned to Earth because their quarters had some kind of infestation in them and no other room could be found for them.

"How many times do I have to tell you?" said McKay, with exasperation in his voice. "I didn't delete anything from the Database. And if I had, I would have told you."

"Then why was your command code used to access the Database at those times?" asked Carter. She was calm and collected; a superior officer questioning a lesser official.

"Maybe someone got my code… I don't know! What I do know is that the system that you say I deleted stuff from is not a system I've ever heard of. Maybe Zelenka…"

McKay never finished that sentence because, at that moment, the computer in front of them began to beep frantically. Carter turned to it, and tapped a few keys, silencing the alarm.

"I'm reading massive amounts of power are being fed into the gate. Hold on… Whoa."

"What?" asked McKay.

"According to this, the power being fed into the gate is the equivalent of….. three fully charged ZPM's."

"But.., but…, that's impossible." said McKay "If even one Zed-PM was connected to the power system, wouldn't we know?"

"Unless their EM field signatures were being masked…" said Carter, but before she could finish her sentence, they watched the inner ring of the Stargate begin to rotate. The five minute time limit was up; the gate was dialing AR1-001.

Carter immediately punched the alarm button and turned on the microphone. "Unauthorized Gate Activation. Soldiers to the Gate Room immediately." She then turned to the dialing computer, and tapped a few keys.

"I can't stop it; someone's logged in as Daniel and given him higher permissions than me. I can't even see the coordinates, someone's masked them!

Chevron One Encoded

"Can't you close the iris?" asked McKay.

"Yeah, hold on." "Closing the iris." she said as she placed her hand on the scanner. It beeped and the Iris closed.

Chevron Two Encoded

"Colonel Carter, Dr. McKay" said General Laundry as he walked into the control room from the meeting room upstairs. "What is going on?"

"Someone in the base has launched the dialing sequence." responded Carter.

"Can't you stop it?" asked Laundry

"No, sir. Whoever did this hacked into the system as Daniel and locked everyone else out of the dialing computer. Not only that, we can't even see the coordinates; someone's masked them from us. I've shut the Iris, though"

Chevron Three Encoded

"Colonel Carter," came a voice over the base radio. "We can't get into the Gate Room. The door into the nearby corridor's been sealed off. The MALP room too, our access cards aren't working."

"Drat" she said.

"Look," said McKay. Do we know ANYTHING about where the gate is dialing to? A name, perhaps?

Chevron Four Encoded

Carter consulted the computer screen. "According to this, the planet's designated AR1-001, but," she said, tapping a few more keys. "There's no entry for it in the planetary database."

"What does that mean?" asked Laundry.

"That someone is trying to get to an unexplored planet, sir"

Chevron Five Encoded

A second later, the Gate Room's left hand door opened. A second later, a MALP came out of the doorway, followed closely by a young boy. He appeared to be directing it, if the laptop he was holding was any indication of it.

"Young man!" shouted Carter into the microphone. "Stop and do not move!"

He turned to them. "Dr. McKay, you really shouldn't mumble you're access code in your sleep. You made it too easy!" McKay looked like he was incredibly embarrassed; he should have been.

Chevron Six Encoded

He walked over to the MALP, opened it, and put his laptop inside; the MALP was already programmed. He just hoped it would work.

Chevron Seven Encoded

"He's dialing out of the galaxy!" said Carter.

"I don't think so." said McKay.

Chevron Eight Encoded

"What?" said Carter.

"That's why there was a major energy spike." said McKay. "He needed power to dial the gate fully."

"What do you mean…" said Carter

Chevron Nine Locked

The Stargate activated, sending out the kawoosh and pulling it back in. He smiled; it had worked. This was short lived, however, as his watch started beeping; it was midnight. He felt massive pain coming on; he had to go now. He reached into his pocket, pulling out a flash drive. He threw it to the ground as he signaled the MALP to move forward. It entered the Gate first, and then he followed as his body began to change.

The last thing he remembered was the sound of the Gate closing, and what looked like two figures approaching him, before he blacked out.

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Tails liked sleep. More than most foxes did, at any rate. However, when Sonic the Hedgehog woke you up, you didn't think about complaining. Not that he would hurt you, but no one wants to hurt Sonic's feelings, unless they want him challenging people to races every five seconds for a month on end. So that's why when Sonic woke Tails up, Tails woke up.

"Tails" Sonic said. His voice matched his appearance perfectly. "Guess what?"

"Shadow's finally beaten you?" responded Tails, slightly angrily.

"He he," said Sonic. "No, but he's getting better. No, there are earthquakes!"

"Earthquakes?" asked Tails, now excited. "Where?"

"I think in the old cave outside of town." Sonic replied.

"Cool." said Tails. "Well, what are we waiting for?"

"That's what I was thinking." Sonic said.

The old cave outside of town was, basically, a large shaft in the ground that led to a small, underground cavern. The only things in the cave were carvings in the walls that no one could decipher, and the outline of a large circle in the back wall. As Sonic and Tails left Tail's workshop and walked towards the cave, the tremors became more powerful, but still not that powerful.

They descended the makeshift staircase built into the shaft carefully; the tremors were definitely getting stronger. Once they reached the bottom of the shaft, they walked down a small tunnel before reaching their final destination. When they reached the entrance of the cavern, they stopped, gaping.

The outline of a circle in the back wall had vanished, as though the earthquakes had disintegrated it. Instead, there was a small cavity behind where it once was. Inside the cavity was an enormous stone ring. It was immediately apparent that this was the cause of the tremors. Within it was an inner ring of sorts, which was rotating, occasionally stopping and reversing direction. Whenever it did, a light along its circumference would light up. So far, six lights were lit.

"What is it?" asked Sonic.

"I dunno." said Tails. Neither of them had seen anything like it. As they watched, two more lights on the bottom of it, one on the right and then one on the left, lit up.

"Should I go see…" said Tails, but before he could move, the inner ring stopped and the final chevron lit up; the dialing sequence was complete. The kawoosh formed out of the Stargate, startling both of them. Tails turned to leave; this was really freaky. But before he could, Sonic stopped him.

"Look." Sonic said.

Out of the Stargate came the MALP. It bumped down the crude steps fashioned in-between the bottom two chevrons, coming to a stop some distance from the gate. A second later, a figure emerged from the Gate; from here, Sonic and Tails could not properly see him. Sonic and Tails cautiously walked forward as the Gate shut down, once again slightly freaking Tails out. As they neared the Gate they took in the symbols comprising its inner ring, and the Gate itself. However, they mainly took in the visitor.

He was a hedgehog; if you looked at him for a few seconds, you would swear he looked like Sonic, but as they drew nearer, they could see him better. His eyes, a deep blue, closed as they approached him. He was built exactly the same as Sonic, but was radically different at the same time. His fur was a smoky grey, almost black. It covered his whole body, like Silver's did, except for his mouth and the surrounding area, like all three hedgehogs. On the palms of his gloves, or at least the one that was visible to Tails and Sonic, was a silver circle and line that ran down to the end of the glove, where it met a simple silver ring that surrounded the end of the glove. He had three quills on his forehead; like Silver's five, they stood straight up. His ears, inside the same color as his facial area, were visible on either side of the three quills. The middle

quill featured a single silver line running along its middle. His remaining quills behind the front one, five in all, curved down. Each got progressively lighter in color as it got smaller, until the tips were silver. His mouth and nose were the same as Sonic's. The single thing that was reminiscent of Shadow was his voice. Although Sonic and Tails couldn't hear him now, they could tell this guy would sound almost like Shadow.

He was holding something. Tails reached down towards the still form and took up the note while Sonic placed a hand over the hedgehog's heart.

"He's breathing." Sonic confirmed. "Looks like he just blacked out."

"Look at this" said Tails.

On the piece of paper, in a hand that looked like it had been carefully written, was

Tails, try the green button. And don't drop it!

Sciron

"Sciron," said Tails "Is that his name?"

"Don't know." said Sonic. This was kind of weird. "What does he mean by 'the green button?"

"Maybe this." said Tails. He had wondered over to the MALP and had noticed a green button on it. As per his nature as a curious fox, he pushed it.

The MALP did nothing immediately. As Tails gave it up as a lost cause, however, the MALP began to shrink. It continued shrinking until it was the size of a matchbox.

"Well," said Sonic. This was getting weirder and weirder. "If that's all, we need to get him somewhere safe. How about your workshop, Tails? You have a spare room, right?"

"Yeah," said Tails. "What about this?" he asked, indicating the matchbox-sized MALP in his hand.

"Bring it" said Sonic. "And like he said, don't drop it!"

And with that, Sonic took up the form of Sciron the Hedgehog as he and Tails made their leave of the cave, and of the Stargate.