Disclaimer: I own absolutely nothing. Harry Potter belongs to J.K. Rowling. Stargate SG1 and any references to it belong to MGM Studios. Star Craft and all of its characters belong to Blizzard Entertainment.

AN: I've been asked why Harry didn't beam himself out of the Corona before the gear. The reviewer (Matt101) stated that he valued lives more than technology. The answer to your question is that the technology could have potentially saved the Raiders from being exterminated. As well, if he'd beamed over first, he wouldn't have been able to get his weapons out.

AN2: If any of you have played the game Resistance: Fall of Man, you might recognize a few things that bear a striking resemblance to said game. I hadn't intended to have another Crossover and the references are for only this chapter or possibly the next one.

Now; on with the story…

January 13, 1998: Milky Way; Earth

"Damn it!" Harry cursed as he was flung through an archway. While in midair, Harry flipped and landed on his feet. He grabbed his Browning since his rifle had been transferred to the Hyperion with the rest of his gear. The only things that Harry had on him were his Browning, his Warp Saber and two grenades.

Harry looked around the room. It was large and had many seating benches that sloped downward. In the center of the room was a dais with a large arch with a red veil fluttering in invisible wind.

"You, put your weapon down!" Harry spun around to see two men in robes pointing sticks at him. They were standing near a door at the top of the benches.

"Tell me who you are and where I am," Harry said. The men started bounding down the benches until they were a small ways away from him.

"Are you an idiot? You're on Earth in the Department of Mysteries in the Ministry of Magic," one of the robed men said. "What are you doing here?"

"I don't know," Harry said. "I was flung through this arch a moment ago but I have no idea how I got here."

The robed man the spoke leaned over to the other one. "He may not be an enemy. Look at his clothes; he's a Muggle, no doubt about it."

"But how could a Muggle get in here, sir?"

"I don't know but I have a feeling that he's telling us the truth. If he can help us against the Infested, I don't care who he is or where he came from." The man turned to him. "Will you please come with us?"

"Sure, I guess," Harry said and followed the men up the benches and through a door.

Harry looked around a circular room. The man quickly opened on door and stepped through. Harry followed him out into a more normal hallway. He followed the men down the hall and to a lift. They got on and Harry felt himself get pulled up for several minutes until they came to a large atrium. Dozens of robed people were running around carrying out orders. One woman who was dressed in black robes with a red crest on the back seemed to be in charge.

The men stepped out of the lift. They walked over to the woman in charge. "Madame Bones, this is the cause of the disturbance." Bones looked Harry over.

"He's a Muggle. How could he have gotten into the Department of Mysteries?"

"You've got me," Harry said and started to twirl his gun around, the safety on of course.

"Who are you?" Bones asked.

"My name's Harry Potter," Harry said. Bones looked skeptical.

"Harry Potter has been missing for seven years," Bones said. "I've seen the boy myself when he was young. He had black hair and the green eyes of his mother."

"What job do you have, Madame Bones," Harry asked.

"I am the head of the Auror force. It is a magical police."

"If you are the head then you must have been one of these officers," Harry said to which see nodded. "Then you would know that jet black hair is a very uncommon color of hair. In a job where one has to be undercover, it would do well to blend in with the crowd. I changed my hair color but look at my eyes. How common are green eyes?"

"You may have a point and you may look like him to an extent but you are far older than Harry would have been by now!"

"I've fought in more wars and seen more things than just about any other living man on the planet," Harry said. "That kind of thing tends to make you grow up a bit. Now, I believe that you are in some sort of military crisis. I may be able to help if you give me the opportunity."

Bones nodded and gave a signal to one of the Auror officers. She led Harry over to the wall of the atrium where they sat down and Bones went into the story.

"Two months ago, the Dark Lord Voldemort, the leader of an insurgent group known as the Death Eaters, began to attack the Magical world in full force," Bones began. "He had a force of about two hundred which is quite remarkable considering our population. The defense was poor but sufficient to repel all of his attacks. Then, one day, Voldemort broadcasted a message over the wireless. He said that he would either rule this country or see it burnt to ashes around him. The very next day, Voldemort unleashed a virus that infected all Muggles, turning them into rabid zombie-like creatures that could only be hurt by the Killing Curse. We've been fighting them for weeks but this is out last stronghold. If they break through the defenses, we're dead."

"The entire country has been taken over?" Harry asked. Bones nodded. "What kind of weapons are they using? How many of them are there? Do they even have technology?"

"The Infested technology is somehow far beyond that of what we believed the Muggles to possess. They have large four legged machines called Stalkers that can move faster than most cars and rifles that can fire eight hundred rounds a minute. Each shot is as deadly as Reductor Curse. None of our spells except for the Killing Curse can break through their armor. Their airships are bringing more and more every day."

"You're a Muggleborn, aren't you?" Harry asked to which she nodded. "I'll make you a deal. I'll help you with this crisis if you help me figure out how I got back to Earth." While this may have been a strange statement, Bones, eager to receive help, shrugged it off as a metaphor.

Just then, a woman came running up to them. She wore something more along the lines of battle robes and had long bushy brown hair. Chocolate eyes were filled with concern and fear. "Commander Bones, the Infested have begun their attack! The front entrance is taking the brunt of the assault as we speak!"

"Calm down Hermione!" Bones said fiercely, getting up along with Harry. "If we are to die here protecting our loved ones, we are going to do it! If you are going to be this afraid, go join the civilians in the lower levels."

"I'm sorry," Hermione said weakly before running off.

"Harry turned to Bones. "Refer to me as Captain Duo from now on. I'll be taking charge of the defense." With that, Harry charged after Hermione.

Harry came to a main entrance where wizards and witches alike were running around; shooting green colored spells this way and that. It was total chaos. Harry observed two guard towers. He ran over to one and ran clean up the wall, a perk of being trained by warriors from all over the galaxy.

Harry reached the top of the tower and looked out at the battle. The sentry at the top had been killed already. Swarms of humanoid creatures with grey skin and six yellow eyes assaulted the defenses with strange machine rifles. A few Stalkers were nearby, shooting machine cannon and missiles.

Deciding to have some fun with this, Harry hurled himself over the edge of the tower, easily traveling eight feet before descending lower. Mid flight, Harry grabbed his Warp Saber from his pouch and activated it. Twisting to avoid rifle blasts, Harry landed in the center of the crowd. With one great swing, Harry killed eight of the Infested.

Twenty of the Infested turned to shoot him. Harry smirked and pressed the Asgard cloaking device on his wrist and disappeared just as eighty rifle shots shot through where he was a moment ago. To the wizards and witches watching the battle, all they saw were Infested humans falling and dieing, cut to bits but an unseen ally.

The Infested humans were shooting everywhere in a mad panic. The mindless super soldiers couldn't see their enemy and had lost over three hundred of their four hundred-strong company. Still more were cut down. The wizard watched in silent awe as a Muggle, as the rumor had spread, was destroying enemies they had never even dreamed of defeating.

The last of the Infested fell down to the ground, dead. The entire engagement had lasted two minutes. Harry deactivated his cloak and his Warp Saber. With a small smile, the Ancient walked towards the line of defense where the wizards stood speechless.

"What are you all waiting for?" Harry asked in a low voice he made no attempt in masking. "Gather the weapons and get rid of the bodies! All the time that you waste here will count against you in the next battle!" That shocked the wizards out of their reverie and they quickly set to work gathering the weapons and banishing the bodies. A few of the Purebloods looked disgusted to be given orders by a Muggle.

"Why should we follow your orders?" one of them asked. "You're a Muggle! You could never harm us! We are far superior to you!"

Harry continued walking and was right next to the man when he spoke. "Just remember, fool, that I'm the one that just saved your pathetic excuse of a life. I seem to remember that you were screaming for your mother a moment ago." The Pureblood turned red and walked off angrily. None of the others challenged Harry.

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Interlude

A few hours later found Harry sitting in a room in the Ministry of Magic examining a Bull's-eye machine rifle that was used by enemy Infested. It was an amazing piece of weaponry. It fired its ninety round magazines in ten seconds on full automatic and each shot was about half as deadly as his Browning's kill setting. It had a TAG setting that when fired created a tracer for all of the following shots, increasing long range accuracy. What confused Harry the most was the weapon's origin. It was Ancient.

Harry had examined the Bull's-eye from every aspect and every time his results were the same. This weapon was an Ancient design, probably used by Ancients themselves. The question was, how did the Infested and Voldemort get them? The wizards couldn't answer these questions as they hadn't paid attention. Harry decided then and there that he would figure out what the hell was wrong on the island.

While he was examining the weapon, he was also making adjustments to it. Since he didn't have his modified SA80, he'd use this thing which was as close as he was going to get. He modified the firing system so that it took exactly five seconds longer to empty a magazine but that made it much more accurate at long ranges. Harry also put another setting into it. His Bull's-Eye could now fire a focused energy beam used from the weapon's ammo. The beam could slice through steel like butter and with concentrated fire could cut stronger alloys as well. Each shot took 45 rounds. With the Ancient design, it was quite easy to manipulate.

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January 14, 1998: Milky Way; Earth; London

Harry looked over the piece of rubble he was hiding behind to see a patrol of infested humans. He was alone on this guerrilla strike because he was still teaching the wizards how to use the Bull's-Eyes as well as taking the Purebloods down infinite pegs. There were eight Hybrids, the most common type with Bull's-Eyes, in the patrol.

Harry popped up and fired rounds at the enemy. He killed the first Hybrid with six shots to the head and three others in the same fashion. The remaining Hybrids dove for cover and started to return fire. Harry took out another one before he got hit in the shoulder, forcing him back down.

Harry put pressure on the wound. Right now there was no time to heal it so he left it and hit his cloak. Harry jumped onto the piece of rubble he was hiding behind before jumping again. It was here that he realized just how high he had jumped. He was easily eight feet above the ground. He landed without injury behind one of the Hybrids. Harry drove his Warp Saber into it and pulled it back out again quickly. The others didn't notice a thing.

Harry rushed over and sliced the head off another one and snapped a third's neck with a kick. The last Hybrid saw a slight shimmer of movement with its enhanced eyes and fired a TAG at Harry. The glowing tracer hit Harry in the chest, revealing his position. The Hybrid fired and Harry cart wheeled out of the way. His Warp Saber deactivated and was placed back in its pouch before Harry fired his Browning at the Hybrid's head, killing it.

Harry straightened himself and deactivated the cloak. These Hybrids were different than the ones he had fought earlier. They looked the same but had quicker reflexes and were smarter. Otherwise they would have never caught the shimmer from the cloak. Harry moved his hand to his shoulder where he had been hit. His eyes widened.

There was no wound. There was just skin and dried blood. His shoulder had healed in the middle of combat. That was impossible. Only the Antoniek, an advanced human race, could heal that quickly and even then it was done with the armbands. Harry didn't have any more time to think as Bull's-Eye rounds shot past his head.

Harry ducked and fired back with the Bull's-Eye. There were six Hybrids and two Stalkers, more than one normal human could handle. (That was the biggest cliché in the universe.) Harry fired a TAG and killed a Hybrid before a Stalker missile exploded a few feet away, sending him flying. Harry flipped in midair and landed, still firing. He grabbed a frag grenade and threw it at the Hybrids. Four of the enemies were destroyed, but the shrapnel barely scratched the Stalkers' paint.

Machine gun fire and missiles were fired at him the entire time. Harry strafed the enemy while avoiding shots but it wasn't doing any good. He flipped a switch and the weapon became the beam cannon. Harry changed magazines before popping out from cover and firing. The yellow laser hit one of the Stalkers where the legs met the body. The beam cut through the joint and hit the power core on the back. The laser cut out after one second and the Stalker exploded.

The other tank started moving around, realizing that Harry was a serious threat. Harry jumped aside, eight feet to the side to be exact, and fired his cannon. The laser hit the missile pack of the Stalker, causing the missiles inside to explode, but the weapon was still extremely dangerous.

A loud hissing sound caught Harry's attention. He looked up and saw a Hellfire missile shoot overhead and impact the Stalker. The resulting explosion hit the power core and the tank exploded. Harry looked around and saw an Apache Attack Helicopter hovering a short distance away with ground forces underneath. Harry quickly ran over to them.

Harry approached the men and saw their patches. They were United States Army personnel, probably here to either destroy the Infested or evacuate the survivors or both. In Harry's mind, they were here to gather survivors and then to place nukes all around the island but that was just his perspective. Harry approached a Captain.

"Who's in charge here?" Harry asked.

"I'm Captain Davis, First Rangers," the Captain said. "Who are you?"

"Captain Duo, Special Air Service," Harry said, referencing a branch of the British Army that he'd heard his uncle talk about when he was younger. "Are you in charge?"

"No, that would be Colonel O'Neill from the Air Force," Davis said. Harry almost wanted to laugh.

"Alright, take me to your CO," Harry said seriously. He had been worried that the Army would be suspicious of him due to his accent but with O'Neill, he'd be alright.

Harry followed the Captain through the ruined streets of London for a few minutes until they came to a command post. Soldiers were running around, carrying out orders, going on patrols, etc. The command post was a simple army tent with a few tables and maps inside. Harry entered to see SG1 pouring over some maps of England and the city.

"If we bring our men up this road, we should be able to flank the Chimera and surround them," O'Neill said to Carter, none of them noticing Harry enter.

"Wouldn't it be more prudent to attack from the air, O'Neill?" Teal'c asked.

"No, those Stalkers have damn advanced SAMs and our attack aircraft would be blown out of the sky," Jack said. "They need to be distracted by ground forces before we can attempt an air attack."

"Why can't we just ask them to tea?" Harry said from behind Daniel.

"Nice joke, Daniel, but these things aren't exactly friendly," Jack said.

"That wasn't me," Daniel said. They all turned around to look at Harry.

"Hi," Harry said cheekily. They all blinked.

"Harry?" Jack asked.

"Yeah, I guess you could call be that," Harry said. "I go by Duo now, though. What's up?"

"You already know, don't you?" Daniel asked.

"Yep," Harry said. "So, what exactly are you doing here? Are you planting nukes or trying to retake the island?"

"Both, actually," Sam said. "We want to take the island back but if that fails then we will activate nukes."

"We're also here to obtain any technology that these Chimera possess," O'Neill said. "What are you doing here?"

"I actually don't know why I'm here," Harry said. "I just got sucked through some kind of wormhole and here I am. Now, I'm going to figure out what the hell is wrong on this wrong on this island."

"You don't know how you got here?" Daniel asked. Harry shrugged and they set the matter aside.

"What do you guys know about the Chimera?" Harry asked. "What few survivors I found called them the Infested."

"It would appear that some terrorist released a virus that turned almost all of the humans on the British Isles into Chimera," Jack said. They have advanced technology that we've never seen before and are much more powerful than any human. They also seem to be excavating something." He handed Harry a photo of Somerset.

The photo was taken by a satellite and therefore not very close-up but what was depicted was still easy to see. It was in a large gorge, Cheddar Gorge, if Harry remembered right. It appeared to be a large tower made of an unknown metal. Various flying machines were moving about around the tower.

"It was excavated, not created," Sam said. "That tower is one of thirteen all over the island. They are home to legions of Chimera."

"What are your plans now?" Harry asked handing the photo back.

"Right now we want to take back London and hopefully get to the…" Jack couldn't finish as an explosion cut him off. They all rushed outside to a terrifying sight.

Over half of the command post was burning. Tanks and vehicles were destroyed and what soldiers that were left were shooting at something that was out of their line of sight. SG1 turned around and saw three twelve foot tall humanoid machines with Gatling guns for arms and missile packs on the shoulders.

"Those are Goliaths!" Harry exclaimed. "What are they doing here?"

"You know what these things are?" Jack asked as he grabbed a gun.

"They're combat walkers with enough firepower to take down an entire company of soldiers!" Harry said as he tagged the machine. "Destroy them or they'll destroy you!"

Harry unleashed a torrent of fire at the cockpit of the lead Goliath. His shots cracked the opaque glass before shattering it and killing the pilot inside as well as the machine as it exploded a moment later. A tank fired a shot at another Goliath, hitting it square in the chest. That walker stumbled back and was destroyed by another shot. The last Goliath was destroyed by Harry using the same tactic as with the first.

"I've never seen anything like that," Jack said as he examined the damage. They had ten tanks left and six Black Hawk helicopters. Two Apaches that were in the air landed. There were eighty or so soldiers. The US had lost over seventy five percent of its fighting force in one battle. "How could we have lost that many men?"

"Be thankful that those were the models used and not later ones," Harry said. "I've seen models that have been three to four times as powerful. Hell, the one that I used was six times as powerful as the ones we just saw. We're in trouble if they have as many of those as they have Stalkers."

Harry looked up and saw a missile shoot over their heads and hit the command tent, destroying the radio equipment and maps. The source of the missile quickly made itself visible. It was a modified Goliath that rather than having machine gun arms had machine guns held in the hands, making it more versatile. The missile launchers had been downsized to almost shoulder plates with six missiles each. It looked just like Harry's first model of the Helios.

"Take cover!" Harry screamed as eight of the new types flew overhead. The soldiers scattered before firing back.

A Helios-model came flying low on a strafing run. It flew right at Harry firing its conventional machine gun. Harry jumped back and grabbed his Warp Saber. As the enemy got closer, Harry jumped up and onto the machine, slicing into the cockpit slightly, causing it to open. Harry killed the Hybrid inside and threw the body out. He jumped in the chair and closed the door, gaining control just before the suit crashed.

Harry flew up and attacked the enemy suits. This mobile weapon's cockpit was exactly like the ones in the Goliaths back in the Koprulu Sector. A small name on the Heads up Display designated the weapon Volt. Harry shot his weapon at one of the enemies, catching the Chimera by surprise and killing the pilot. Without a pilot, the weapon crashed into the ground.

Harry back flipped the suit and fired at another Volt. He hit the enemy in the cockpit, repeating the first kill. The other Volts, realizing that their wingman had turned enemy started to attack Harry rather than the humans on the ground. Soon enough, Harry was dodging five enemy suits. The Hybrids were almost as skilled as he was so it was a tough fight.

Harry dashed to the side and shot an enemy in the cockpit. It was the most efficient attack as he didn't have an explosive weapon other than missiles. Harry flipped to avoid a stream of fire and fired a missile, destroying the attacking Volt's gun but little else. Harry aimed his gun and fired, destroying the suit. The remaining three suits attempted to flee. Harry fired two missiles, destroying two of the suits but left the other one.

"Jack," Harry said over the radio. "I'm going to follow this guy. You've done all that you can do here. Either retreat or get out of the city. Either way, you can't stay here. You'll have Goliaths all over your position in a matter of minutes!"

"Roger that, Harry," Jack said. "We'll pull out of the city. We'll contact you, don't worry."

"Understood," Harry said before speeding off towards the fleeing suit.