A/N: Yes, this is a triple crossover. It is also an AU for all three (obviously). I've given you the moments that this story splits from each plot. I've also posited that Sera is a cutoff human colony beyond human space.
Half Life 2: AU from the end of Half Life 2, where the G-Man takes Gordon and Alyx. No vortigaunts show up.
Halo: AU from just before the end of Halo 3 – the Forward Unto Dawn survives the explosion intact.
Gears of War: AU from just before they kill the Berzerker.
This is a reformatted version, if anyone's wondering. I've decided to make it clear as to whose perspective each scene is written from. Also, I've made it clear that these are seperate scenes.
Gordon Freeman, location unknown
"Rise and shine, Mr. Freeman, Miss Vance. Your services are once again required."
Gordon saw the G-Man's face in front of him. Instinctively, he looked to his right, where he saw Alyx. Her face was clearly visible, but her body was obscured.
"This task will be the most difficult you have ever taken on. To assist you, I have provided allies and special equipment. Your allies, in particular, will be quite reliable."
The G-Man's face was replaced by a metallic bulkhead. Gordon noticed that there was a pane of plexiglass in front of his head. He felt with his hands, and confirmed that he was wearing a helmet. He turned to Alyx. She was wearing what seemed to be a spacesuit version of the HEV suit. He looked down at himself – he was wearing the same thing. Gordon gave Alyx another look. That HEV suit looked pretty good on her.
It seemed as if the G-Man had equipped both of them with the same items. They each had an enhanced gravity gun and crowbar. On the floor was a PDA. Alyx picked it up and turned it on. She began reading. "The Mark V-B HEV suit contains most of the features of the Mark V-A. It is modified to allow the user to survive in an airless environment for up to 4 hours on internal power alone. With external power sources, it can run indefinitely. The suit also contains voice-activated environmental sensors…"
"Environmental check," Gordon spoke.
"Internal environment is nominal," came a computerized voice. "External environment: oxygen/nitrogen atmosphere. Pressure: 0.8 atmospheres. Temperature: 285 Kelvin. Background radiation: minimal. Toxins detected: none. Environment safe."
Both Gordon and Alyx removed their helmets for comfort. The air was somewhat chilly and thin, but breathable. Gordon looked around. They were inside some kind of armory, judging by the weapon racks lining the walls. There were a few guns still there. Alyx examined a rifle.
"These are definitely human weapons, but not any I've seen before." She handed Gordon the rifle. It was slightly larger than an M-16, and sported a scope. "A sniper rifle?" he wondered aloud. "Barrel's too short," Alyx shook her head.
They examined the other weapons. There were semi-automatic pistols, submachine guns, and a double-barreled rocket launcher with the letters "UNSC" stamped on the barrel.
"What the hell is 'UNSC'?"
"United Nations Space Command. And who the hell are you?"
Standing in the doorway was a seven-foot-tall figure clad in iridescent green body armor. He was pointing a rifle at them.
Master Chief, UNSC Frigate Forward Unto Dawn, location unknown
Master Chief's head hurt. They had spent the last eight hours trying to reconcile two vastly different views of reality. And even with the combined brainpower of an MIT-trained scientist and Cortana, it had not been easy.
According to Master Chief, Cortana, and the Forward Unto Dawn's computers, the year was 2553. Earth had forged a shaky interstellar empire. There had been no contact with alien lifeforms until 2525, when the Covenant destroyed Harvest. Since then, most human worlds had fallen. The Covenant had launched an invasion of Earth, but they had been repelled.
But according to Dr. Gordon Freeman and Alyx Vance, the year was 2024. Contact with alien life came during the Black Mesa incident in 2004, which brought Xen lifeforms to Earth. Subsequently, the Combine had successfully conquered Earth, and established a totalitarian police state. As far as they knew, no human had ever traveled within our universe beyond Lunar orbit, but they had visited other dimensions.
Eventually, Freeman had proposed that he and Vance were from an alternate dimension. A scan of the Forward Unto Dawn's historical database allowed them to identify the point of diversion. In their history, the US government had established a program to develop portal technology in 1959. This led to the construction of Black Mesa Research Facility, and ultimately the Black Mesa incident in 2004.
In Master Chief's timeline, however, the Congressional bill that established the program had been defeated and never resurrected. There was a mention of Gordon Freeman – in 2012, he and Dr. Eli Vance (Alyx Vance's father) had produced a groundbreaking paper on space-time dynamics. It was mentioned as one in a series of papers that led to the development of the Shaw-Fujikawa drive.
"OK, I think I understand," the Arbiter said. "But I have one more question. What is that weapon you are carrying?"
Vance smiled. "This is the Zero-Point Energy Manipulator. But we just call it the gravity gun."
"The original version was used primarily for handling objects that are either hazardous or heavy. Gordon here was probably the first to use it as a weapon. It didn't work on living matter, but he could throw debris, barrels, saw blades, you get the idea."
Gordon spoke up. "Recently, I went through a confiscation field that took all my other weapons. It did something funny to my gravity gun – rather than taking it, it amplified its power and allowed it to affect living matter."
"It sounds like an impressive weapon, albeit one that would take some training to use," Master Chief commented.
"Well, now that I think about it, everyone who has used it has a degree in physics," Vance mused. "Even I have the equivalent of a college-level education."
"Funny, I pegged you as a double-E," Gordon said.
"I dual-majored."
"Double-E?" the Arbiter asked.
"Electrical engineer – circuitry and the like," Master Chief explained.
"Well, maybe you could have a look at our Shaw-Fujikawa drive," suggested Cortana. "It's busted."
Master Chief thought that Cortana was joking. So he was surprised when Vance and Freeman offered to have a look at it.
"I mean, it's far more advanced than anything from our time, but we have our own teleportation system – and according to the archives, my work in your timeline led to the development of the Shaw-Fujikawa drive," explained Freeman.
"I'm coming with you," Master Chief said. "No offense, but I am more familiar with this technology than you."
"And what should I do?" asked the Arbiter. "I wouldn't know how to repair a Covenant Slipspace drive."
"You can scout the ship and inventory our equipment – figure out our food and ammo situation."
"Agreed."
Alyx Vance, UNSC Frigate Forward Unto Dawn, Location
The Shaw-Fujikawa drive was more advanced than Alyx had imagined. She couldn't figure out how it all worked. Cortana finally explained it to her. She didn't understand the details, but when she got a look at the innards of the drive, she was able to figure out what was wrong.
"Drive's busted," she told Master Chief as she pulled her head out of it. "It's half-melted. We'll need a new one."
He swore, then contacted the Arbiter.
"Arbiter, our Slipspace drive is busted. You got any better news on your end?"
"Most of the weaponry and ammunition was taken by your warriors as they disembarked; however, there is enough left to sufficiently arm the four of us. As for food, I believe I have found the galley – but I do not know how much food humans eat in a day. I would normally eat three of these ration packs each day."
"Good – that's the same as us."
"Chief," came Cortana's voice, "I've got good news. There's a habitable planet in this system, on the far side of the star – that's why I didn't see it before."
"Any sign it's inhabited?"
"Affirmative. I'm detecting several satellites in orbit. They seem to be of human construction."
"Set a course."
Delta Squad, inside the Tomb of the Unknowns, Planet Sera
"WAAAGH!" the Berzerker cried as it nearly turned Marcus Fenix into roadkill. Instead, it smashed through a doorway. One more to go, and they would have it outside, where they could use the Hammer of Dawn.
"Delta Squad, this is HQ, do you copy?" came a voice from his com.
"HQ, this is Delta Squad," he whispered. "We are inside the Tomb of the Unknowns dealing with a Berzerker."
"Copy that, Delta Squad. We have reinforcements en route to assist you. Try to lure it outside."
"Roger. Delta Squad out."
Dom stealth-ran across the room, then gave Marcus the "thumbs-up" sign. Marcus returned the gesture.
Dom fired another shot at the Berzerker. It charged him, but he expertly dodged out of the way, allowing one more door to fall victim to the Berzerker's might.
Across the courtyard, Dom saw four figures moving. The reinforcements? Why hadn't they established communications?
"HQ, this is Delta Squad. Request communications with reinforcements."
"Setting up link now."
A heavy male voice came through the line.
"Delta Squad, this is Lambda Squad. We have a visual on the target. Request permission to fire."
"Lambda Squad, do you have heavy weapons?"
"We have a rocket launcher."
Hmm. Rockets weren't normally issued to infantry, but they might work in this case.
"Fire away, Lambda Squad."
A rocket plume came from across the courtyard, making direct contact with the Berzerker. Sadly, all it seemed to do was make her angry.
"RAAAGH!" It charged towards Lambda Squad. Marcus feared that one of them might be hit.
What happened instead was that the Berzerker was flung backwards onto her back. Marcus stepped out and took aim with the Hammer of Dawn. As the orbital weapon struck the Berzerker, she screamed in agony.
"Hit her again!" Dom called.
A few shots later, the Berzerker was dead. Now it was time to meet Lambda Squad.
As they emerged, Marcus was stunned. They did not look like anything he had ever seen.
The strangest one was about eight feet tall. He was hunched over, and had a strange mouth. His armor was shiny, with ornate designs that seemed very out-of-place for a warzone. A blade of glowing blue-white energy was in his hand. He did not look human.
The second was a seven-foot-tall figure encased in green iridescent armor. His rifle was rather strange - it was longer than a Lancer and sported a scope, yet it looked too short for a sniper rifle. His face was hidden behind an opaque visor.
The last two wore orange armor - hardly stealthy. The Greek letter lambda was imprinted on the front of the armor. One of the people in orange held a giant, two-barreled rocket launcher. He had a short beard, and glasses.
But it was the last one that caught his eye. She wasn't particularly attractive, but she was female. And she had a very strange weapon in her hand. It glowed blue-white, and featured three prongs on the front.
"Who the hell are these people?"
