To Synergy's Duality: Well, the places I've gone to don't quite go into so much depth, so some parts were open to a bit of interpretation. Besides, its fanfiction, and I like to put a little twist on things ;). By the way, if you can tell me where you got that sort of info, I'll be sure to make a few revisions.

Also, on the fact of cleanup, in terms of headcrabs and other aliens, I've seen plenty of Combine guys in the game fighting against the little buggers, but never have I seen a Vortigaunt actively kill a headcrab for the Combine.

Chapter 2: Pest Control

Location: City 17 Residential Block 4
Status: Secure

It was a quiet day on the outskirts of City 17. People going to and from work, Civil Protection officers milling around and harassing random pedestrians, and surveillance drones hovering around. All in all, it was a normal day in City 17. That is, until missile trails were seen in the distant sky.

Civilians took a second-long glance at the trails of smoke, shook their heads in pity for the poor bastards on the other end of the missiles, and went on to their normal duties. The Civil Protection officers didn't even bother to turn their heads.

Location: City 17 Sewage Treatment Plant 9
Status: Infested

"Six, you are clear to fire."

A sharp crack filled the sky, and another zombie hit the ground with a loud, meaty smack. Six, perched atop an old pumping tower, reloaded her rifle and resumed firing. Unsurprisingly, more zombies began shambling forward, as if they were all lining up to be shot first. All they had to do was drop a few pounds of rotting beef on the concrete, and the headcrabs would start crawling out, like flies to a feast.

God these things are dumb. One thought as her other five squadmates opened up on the crowd of zombies. All of these things were once human, Resistance sympathizers actually, but now they were just pests that needed to be cleaned up, but nothing frustrated One more than pest control. All the years she and her team spent training for anti-terrorist operations was going to waste in the wake of the Combine's "crabbombs", missiles that housed warheads full of headcrabs rather than explosives. Unfortunately, the little bastards had the habit of multiplying like rabbits when they found hosts, and Kill Team 17 was always expected to clean the mess up. If only they would stop using the damn things!

Meanwhile, Two and Three were deploying manhacks and sentry guns to keep any zombies from flanking them and attacking from behind. The manhacks immediately began zig zagging through the air and started to shear zombies apart. The sentry guns immediately began firing on everything that came within their line of sight.

"Ghouls! Two o' clock!" Five yelled through the radio.

One turned to her left and caught three gray blurs dashing across the roof of a nearby equipment shed. "Ghoul" was the term coined for the second variation of zombie, which were more skeletal, quick, and aggressive than normal ones. These ghouls managed to leap over the line of sentry guns Two and Three deployed, and started knocking the weapons over. The sentry guns flailed and fired wildly in the air as the ghouls dashed past them, making their way towards Six's position.

One raised her pulse rifle and fired at the ghouls. Good as Six was with her rifle, she couldn't possibly kill all three ghouls before they reached point-blank range, and as fast as the ghouls were, none of them could outrun a pulse round. The ghouls twitched as they were torn apart by pulse rounds and fell to the floor, dead… again.

"Two, Three, reset those sentries. Four, Five, with me. We're going to clear this plant." One said calmly through the radio.

"What about the zombies up here?" Five asked.

"Air support will take care of that." The moment she said that, a Combine helicopter passed by over their heads, pulse gun blazing. About a dozen zombies were mowed down in just one pass, and the helicopter held its position overhead, firing at everything that moved. Four and Five quickly dashed over the entrance to the water treatment plant. Four kicked the double steel doors open as Five lobbed a pair of fragmentation grenades inside. For a brief moment, One caught several fuzzy, human-shaped silhouettes as the grenades exploded.

"Four, Five, go!" One yelled.

Pulse rifles ready, both squadmates dashed inside like black lightning. There were intermittent flashes of gunfire and shrieks of zombies as they were gunned down. One kept watch over the door as Four and Five backed out of the door.

"Status."

Four looked up, her mask blocking any sign of emotion, "Area clear. All lifeforms present and accounted for."

One keyed her radio to the gunship's frequency and said, "Gunship, do a sweep."

"Sweeping," replied the gunship, "reading six human-sized lifeforms."

"Confirm six lifeforms, Gunship."

"Confirmed. Six lifeforms read and accounted for."

One nodded. Four and Five did a good job of clearing out those damned headcrabs. One was about to key her radio to call in for a dropship, when another, unfamiliar voice interrupted her on the radio.

"Not a bad show," the voice on the radio cackled, "pity that such skill and efficiency is wasted on such a…" the voice paused as if the find the right word, "mundane task…"

"Who is this?" One demanded, but all she heard was static. She keyed back to the gunship's frequency and asked, "Gunship, did you record any unauthorized transmissions during the last thirty seconds?"

"That's a negative," the gunship pilot replied, "channels are all clear. No signs of any anomalies."

Two turned her head and asked, "One, something wrong?"

One shook her head. "No, nothing. Nothing at all."

Location: City 17 Train Station 2
Status: Secure

The last train of the day rolled to a stop in the station. This train was bringing back workers who were sourced out to City 14 for expansion work its Citadel, though there weren't very many people in. There were at most, ten or twelve people on board. As they began to get off the train, one man seemed to stand out from the others. He stood a little a taller, showed a bit more energy in his movements, and a determination in his eyes that everybody else around him lost years ago.

He glanced briefly around the area, taking in the unfamiliar surroundings. It was ironic that he spent the last decade or so in another dimension, only to return to Earth and feel even farther away from home than before.

Realizing that he was beginning to attract attention from the guards, the man straightened out his glasses and followed the other passengers to the security checkpoint. He did not know why he was here, or what he was going to do, but Gordon Freeman was in this twisted future for a reason, and he was determined to find out.