At the other end the corridor divided in two, with little pictograms on each wall giving information and instructions to staff. Gordon frowned. He knew Aperture were aiming for the kind of informal minimalism that had been trendy in the years before the resonance cascade, but to him it looked a bit childish. Give him a good old-fashioned training hologram any day. Back at Black Mesa he'd been secretly hoping to get a holographic assistant of his own. No much chance of that now, although maybe it was something Dr Kleiner would reinstate to train his army of scientists and technicians. They studied the directions toether. The right-hand corridor only had a single symbol, indicating a ship. Well, that was clear enough.

"I'll go down this way, check the coast is clear," Alyx said, leaving him with the left-hand corridor. He wandered down it, senses alert, until he came to a door labeled with a stick figure, diving through some sort of hoop. He frowned again. A swimming pool?

When he went inside, there was what looked like a large laboratory, with white walls and benches around the edges. There was a scale painted along one wall, and a cube in the centre of the room, covered with different surfaces on every side. The benches had cabinets below them, and the one on the far end had swung open. He gasped when he saw what was inside. It couldn't be another grav gun, because as far as he knew Eli had only made one, and the end was also slightly different. It was orange too, though, and it had the same oddly comforting heft.

When he stopped to think about it, he wasn't thrilled by the fact that he now found weaponry intriguing, let alone comforting, but at the same time, he really wanted to try it out. He raised the gun, fired at the nearest wall, and… nothing.

Well, not nothing. A weird silvery-grey oval appeared on the wall in front of him. The surface appeared rippled, yet it was completely flat, invisible from the side. He touched it, curious, and what felt like a very mild electric shock ran up his arm. On reflection, he thought, he should probably be pleased. He had fired a completely random weapon into a wall only a few feet away from him. For all he knew it could have set all the oxygen in the room on fire, or released some sort of horrible alien, or at the very least given him an embarrassing ricochet injury. Feeling glad that Alyx hadn't been there to see him, he returned the gun to its locker and headed back off down the corridor.

He linked up with Alyx at the entrance to the gangway, but the door was locked. Slightly further down the corridor, another door revealed a plant room. It was only sporadically lit, by what looked like large sparks. They were periodically ejected from a device on one wall, went bouncing around the room, and then dispersed. Gordon pricked up his ears. The sound they made was remarkably similar to the noise the spheres of energy had made in the Citadel. Alyx turned to him.

"It looks pretty dangerous in there…"

"Don't worry." He stepped forward and tapped his breastplate, liking feeling able to protect her, a situation that arose all too rarely. Timing it to avoid the sparks, he slipped through the door and then turned to study the room. The wall opposite the dispenser contained what looked like a cradle, but it had been pried loose and was hanging by wires, leaving the sparks to bounce off the bare wall below, creating a black scorch mark. The sparks would fly around the room for a while and then wear down. Obviously, the spark needed to go into the socket. Again, like the Citadel. If only he had the uber-Grav gun, he'd be able to grab the spark and put it in the socket, no bother. But what to do now… He looked at the problem for a while. The sparks went bouncing around, and he wondered if there was any way of deflecting them. Then he stepped back and looked at it again.

You know, he told himself, for an intelligent guy, you can be quite stupid sometimes.

He used the Grav gun to lift the cradle, lining it up with the scorch marks. When the next spark arrived, it fit neatly into the socket. There was a humming sound and a clunk as the door locks were released. Gordon released the cradle, and it swung back against the wall, loose on its wires. Studying it for a moment, he saw that judging by the chips and scratched surrounding it, it had been torn out of the wall. There were some reddish-brown stains mixed in with the damage. Gordon would wish later that he'd paid more attention to these.

The ship was resting awkwardly on its side. That would make getting around inside more difficult; still, that couldn't be helped. Alyx made her way down the gangway ahead of him. The deck was listing towards them and they were forced to scramble up it until they reached the door into the superstructure.

Inside, a set of stairs took them below decks, ending in an ominous-looking expanse of dull water where the lower decks had flooded. Gordon felt cold just looking at it. This sort of thing was just his luck. Turning to Alyx, he was surprised to see what almost looked like relief on her face.

"Guess that's as far as we're gonna get… let's go back on deck, we need to find a way to blow the whole ship."

"I can go through there… I don't mind." He did mind, of course. His suit would protect him from physical harm, but he remembered lying on the snow, fighting to breathe after his previous surprise immersion. It wasn't an experience he was keen to repeat. But he had taken this task upon himself, to disrupt the Combine's ability to bring reinforcements through, and thereby secure a possible future for Alyx and himself. Choosing his own objective instead of simply being sent from point to point was a relatively new experience for him, and he was determined to do it properly. What if they destroyed the ship around the vital technology, but it remained intact and sunk through the ice, waiting for the Combine to come back and use it? Besides, while he did want to destroy it, he wouldn't mind at least getting a look first.

"Alyx… I don't think…"

Her eyes flashed. "You want to use it, don't you?"

He gasped, feeling guilty, and then angry because he had nothing to feel guilty about. He cursed his inarticulacy, because while he wanted nothing more than to explain his reasoning to her, and reassure her that he would follow her father's wish, all he could manage was an indignant "No!"

"I heard what Dr Kleiner said." She was backing away, shaking her head, and he could see tears in her eyes. Her sudden distress alarmed him, and he stepped towards her to try and comfort her. But she was already composing herself. It was the way she'd looked after he'd freed her from the Stalker on the train, after the portal storm had swept across them; devastated one moment, and then raising her guard, forcing herself to become calm the next. To know that he was the one who had upset her like that, even unintentionally, was horrible. He encircled her with his arms, very gently, his heart pounding so hard he was sure she'd be able to hear it. She sniffed back her tears, wiped her cheek roughly, and looked straight back at him.

"You're right," she said, but her voice was flat and dull. They moved back to the edge of the water together. Gordon hadn't had much luck with relationships in the past, so the feeling of annoyance, shame and downright confusion familiar to most people after they'd managed to upset their partners was a new one to him, and he felt awful. He stared at his boots, then tried to meet Alyx's eyes.

"Will you wait here for me?" She nodded, pulled some charges out of her pack and handed them to him. Then there was nothing left for him to do but jump. The shock was reduced as he knew what was coming, but the cold itself seemed worse. He let himself sink to the bottom then pulled himself along the walls, looking for a way up. He broke through the surface and dragged himself up onto a ledge, gasping noisily. Once he got his breath back, he set off deeper into the ship, making his way awkwardly along the slanted corridor.

Gordon initially didn't pay much attention to his surroundings, as he was sunk too deep in thought. He didn't understand why she'd become so upset so close to their goal. They'd been following her dad's wishes when they... her dad.

For an intelligent guy, he really could be quite spectacularly stupid.

When Gordon had answered his phone and heard the news of his own father's death, he had gone back to his dorm, locked himself in his room, and cried. His roommates had rallied round him, made him cups of sweet tea, and within a day or two he'd been coping. He hadn't cried at the funeral, hadn't cried again until almost a year later, when the pressure of studying for his finals became suddenly too great. It had taken him a while to realize that he was actually still mourning his father, that the stress of the situation had simply brought it to the surface.

Following Eli's death, Gordon had wanted to be there for Alyx, but he'd been very injured, and in his weakened state his emotions had come flooding back in and overwhelmed him. The guilt he felt over what happened at Black Mesa, and the pressure of so many people considering him the One Free Man, had combined and produced what he now thought was some kind of nervous breakdown. Alyx had been the one that had brought him through it and out the other side. He'd thought she was getting over her own grief well, but it seemed she'd just been burying it in her desire to get to the Borealis and fulfill her father's wish. And now, so close to their objective, the tough exterior he admired so much had finally cracked.

He was pretty proud of this insight. Generally speaking, he wasn't that good at emotional stuff, but Alyx had really brought it out of him. The desire to be back with her and comfort her was overwhelming. They could just blow the whole ship, then check for whatever it was in the wreckage. He could hit it with the crowbar to make sure. Gordon grinned and reminded himself to use that line on Alyx. He loved making her laugh. He was going to heal her the way she'd healed him.

He was about to head back to the flooded section, when he rounded a corner and saw something that took his breath away. A corridor of rooms containing bunks and portholes branched off at either side. He thought he saw shapes in some of the bunks, and his suspicion was confirmed when he came across a man who had clearly hanged himself. In the next room, a woman was slumped against the bulkhead, a pistol in her hand. Gordon caught his breath, disturbed. He'd seen people in City 17 who had clearly taken their own lives, but it was the middle of a warzone, so it had seemed less surprising, although still upsetting. But for these scientists to have committed mass suicide troubled him deeply. Aperture had been a popular choice for work experience and recruitment fairs; these could be people Gordon had known. He stepped into the centre of the room. The bodies had clearly been dead for years, but even so, they had been well preserved by the cold, and expressions of horror were clear on their faces. He was about to leave, when a voice rang out, making the hairs on the back of his neck stand on end. It was a female voice, oddly familiar; cold, but with a hint of malice.

"As the sole surviving employee of the Aperture Science Collaborative Research Division, please make your way to the control room."

Gordon frowned. He certainly wasn't an Aperture employee.

"Your fellow Collaborators have been subjected to a series of mental and psychological tests. The results were…" an almost imperceptible pause… "disappointing. Please make your way to the control room."

Gordon stood still, trying to identify the source of the voice. He identified a moving camera in the corner of the room, at the same time as a red beam of energy came shooting out, singeing his arm and making him wince. He raised his crowbar, intending to destroy it.

"Attempts to interfere with the Aperture Science Employee Constructive Criticism Device may result in further criticism." He snorted and raised his crowbar, but the camera zapped him again, in the chest this time. At that point Gordon decided discretion was the better part of valour. He couldn't really afford to lose the health points. He stepped back into the corridor and stopped, astonished. The panels had shifted, somehow, and the direction he'd arrived in was no longer open. Sighing, he headed in the other direction, towards what he suspected must be the control room.

As he crossed the threshold, the door slid shut behind him, seamlessly obscuring the exit. He had expected something of the sort, and dived for the cover of a console as he raised his machine gun and sighted the familiar camera in the corner. The voice rang out again, a digital sing-song.

"You wouldn't do that, if you could see what I can see…"

He stuck his head out cautiously. Alyx was on the monitors. She was crouching on her haunches, checking her gun, then she stood and stretched. She crossed the room, then crouched down again. Waiting for him. He stood up warily, facing the camera.

"What do you want?"

"Push the button to open the door." He looked over and saw the panel, hesitated with his hand over it, and felt the burn of the laser again, like a prompt. He saw sudden movement on the monitor. There was another camera on the wall behind Alyx, moving to point towards her. He gave a growl of frustration, and hit the button. The workstation became surrounded by what looked like blue flames, and he heard a rushing sound. An alarm was blaring, but it sounded a long way off. The last thing he heard was the voice again, and there was definitely more than a hint of malice overlying the superficial helpfulness this time.

"Did you hear me say door? Did I say door? 'Cause I definitely meant portal." Then everything… flipped.

The air was suddenly warmer and more humid, causing him to sweat inside his suit, and there was an unpleasant smell in the air. The floor was echoing metal underfoot. Gordon opened his eyes, but he already knew where he was.

Gordon had read the sci-fi story Of Men and Monsters for a book report in high school, and he was once again reminded of it now. The scale of Combine architecture was just wrong. It was too big for a human to comprehend. He had landed in some sort of chamber, three walls of which were lined with the familiar metal that looked like tarnished bronze. The wall behind him was a blue rock, maybe the ore that the metal came from, and it rose into a great outcropping, facing a curved glass sheet high up in the opposite wall. A metal tube led up to the screen. Gordon suspected he knew what was behind there. He went back to the console, and found that it was still getting power from somewhere. Looking at the buttons and dials, he thought you could probably program it with different co-ordinates, maybe even change the size of the portal. If he took a little time…

An alarm began to sound, and he knew he was out of time. He looked up at the jingling and rattling sound of fast approaching Combine troops. He had almost no ammo left, and there could be literally thousands of them; an unlimited supply here on the homeworld. He fired anyway, not wanting to accept that the situation was hopeless. He had brought the Combine the thing he had been meant to destroy, and so he knew what he had to do now. As Barney would probably put it, he was totally boned, and there was only one way out. Part of him shied away from the thought with horror; but he forced the implications to the back of his mind, and concentrated on diligently placing his charges and setting the detonator the way Alyx had shown him. He had brought a few grenades with him, and he shoved them deep into the wiring for luck. Then he retreated to a little alcove, and watched as the first troops approached the workstation.

He considered for a moment adopting some kind of heroic posture, or else saying something clever or impressive. But Gordon Freeman was ultimately a very low-key kind of guy, and so he just waited until as many Combine as possible were surrounding the console, shrugged, and then pressed the detonator, destroying the portal device and trapping himself on the Combine homeworld.

The room was filled with smoke, and his ears were ringing. He was trapped. He felt his legs might give way beneath him. He was trapped. He could feel the panic rising, and grabbed onto a metal beam for support. Breathing deeply, he assessed his situation, and gradually calmed himself. He had discovered the lost technology of the Borealis and destroyed it before the Combine could use it, like Eli had wanted, like Alyx had wanted. It was one of the only times he'd gone against Dr Kleiner's advice, but he thought his mentor would forgive him, eventually. He couldn't see a way of getting back, but he was alive and relatively healthy, and he could at least explore, and find out as much as he could about the mysterious occupying force. It was unlikely he'd ever get to tell anyone about it, or use the knowledge in any way; but the objective of science was the pursuit of knowledge for knowledge's sake, and he was nothing if not a scientist.

Gordon made his way through the structure, the Citadel of all Citadels, always aware he was being hunted. He hid and crept and occasionally killed, his footsteps leading him ever upwards. At first he thought he was doing it intentionally, trying to retrace his steps from Citadel 17; but after a while he realised he was feeling a pull, an almost subconscious compulsion. He stepped through one of the folding metal doorways and was struck by how high up he was. He was standing on a rocky projection, high above the ground below, facing a glass screen. He felt the familiar pressure in his ears, and clutched his crowbar for reassurance, but found that he couldn't move.

One of the giant sluglike Advisors moved into place behind the screen, and studied him. The pressure on his head was unbearable, but he couldn't flee from it, he was pinned in place to be scrutinized. There was an emotional component to the pain, too, a message that he felt rather than heard. He was all alone, surrounded by an entirely united force, whose sole objective was to destroy him. All humans were alone, weak, and he had just denied them the protection the Combine offered. He was helpless before the creature's conciousness. Eventually, it seemed to decide it had tormented him enough. The glass screen slid back, and he was being moved closer, suspended in the air. His jaw was slack, his limbs heavy; and it was getting harder and harder to breathe. He felt sick and weak with horror as the proboscis moved closer to his face.

When he had set off to explore the Citadel, he had taken his last grenade and carried it in his left hand, cocked. After Alyx had explained the Stalkers to him, he knew he definitely didn't want to be taken alive. That grenade slipped from his numb fingers now, and the pressure on the safety lever was released.

The blast threw him against a wall, and then he was falling, tumbling down the entire height of the chamber. He was vaguely aware of a horrible squealing sound, and the shattering of glass. He smashed through some kind of cover, then he hit the ground. There was a sickening crunch, which he was only able to relate to himself when agony shot through him. Something warm and wet was pattering to the ground all around him. The suit was bleeping, warning him his death was imminent with its usual disinterest. He tried to look around, but moving made the pain in his head and neck worse, so he lay still.

A weary peace began to steal over him. If he had to die, then an explosion on an alien planet that was quite possibly in a different dimension was a pretty awesome way for a scientist to go. He wondered if Alyx and Barney had made it back to the helicopter. The thought of Alyx made him smile. He'd done it for her, and he wondered if she would ever know. Then, as his life drained away and his thoughts grew simpler, he just remembered her good smell, and the weight of her head on his shoulder; and he wished that she was there with him as everything went dark.