For the first morning in several weeks, Eli Vance was up before his energetic daughter. In truth, he had barely slept that night. During what little sleep he was able to obtain, he found himself plagued by nightmares. In the early hours of the morning, he was transported to what seemed to be another world: a sea-green sky, jutting pillars which thrust themselves upwards, and unspeakably strange creatures the like of which he had never seen. More than this, he also dreamt of the face of the man who had supplied Black Mesa with the crystal which would be the centrepiece of today's great experiment.

Waking damp with perspiration and with a rapidly-beating heart, he felt silly to be so shaken by the thought of the nameless man, but the stranger's appearance and manner still disturbed him. He had met him just once before and had noted his pale grey skin, luminous green eyes, and the odd stress and emphasis he put on certain words. What disturbed Eli more was that he seemed to be one of the few people the green-eyed man had shown an interest in, that is to say, Eli had noticed the man observing him from afar. For the most part, the briefcase toting man disregarded pretty much everyone. Eli was by no means the highest-ranking employee at Sector C's Anomalous Materials Laboratories. That position was occupied by Dr Breen. Indeed, it seemed to irritate Sector C's administrator that the grey-skinned man was almost entirely apathetic to him. Breen and the man had shared only one private conversation when he had first arrived in the facility, but Eli had heard none of their words.

Since then, the man had been wandering about the facility freely and alone, as if he expected a great change to take place there at Black Mesa, and wanted to tour the facility before that change took place.

To say Eli was nervous about the upcoming experiment would be a great understatement. He and his colleagues knew little of the anti-mass-rich substance that had recently arrived, so no one, not even Dr Breen, could vouch for its stability. Technically, Eli had the authority to object to the experiment, as did all scientists working at Anomalous Materials, and abort the upcoming test, but he knew his colleagues would resent that. His fellow scientists, their administrator Dr Breen especially, were eager to put the mysterious crystal, an extremely pure sample, through the anti-mass spectrometer and observe the results. The only scientists that did not sympathise with those feelings were Isaac Kleiner, who shared Eli's apprehension, and young Gordon Freeman, who rarely voiced his opinions, but nonetheless volunteered to be the one to insert the sample into the anti-mass spectrometer.

Alyx Vance was five years old and as spirited as any girl of her age. She bounded into her parents' room, clambering onto their bed, waking her mother, Azian. Eli, who had already been less than half asleep, staring at the ceiling with tired eyes, propped himself into a sitting position to welcome his daughter.

'I had a really good dream', said Alyx excitedly.

'What about, baby?' asked Eli. Azian, next to him, was still stirring and groaning softly.

'I dreamed I had a dog.'

Eli sighed inwardly. This again.

'Alyx, we've told you already. Pets aren't allowed at Black Mesa. This is no place for an animal, least of all a dog. There would be no space for it to run around.'

Alyx didn't seem discouraged.

'Yes, but the one in my dream wasn't an ordinary dog, it was a robot dog. It was made of metal and had a triangle face with a big red eye. Remember last week, I saw a big robot from the tram. It was moving crates. If those are allowed at Black Mesa then why not a robot dog? You're always saying that it's dangerous here. A dog could protect me.'

'And where would we get a robot dog, baby?'

'You could build one. I know you could do it. You're the smartest man in Black Mesa.'

Eli smiled at that. Could he construct a robot for Alyx? Maybe. That is, with a little help from Kleiner. But he had far too much on his mind to think about that now. Today was too important a day to worry about anything other than the experiment.

'I'll think about it, Alyx.'

Alyx gambolled out of the room with glee. It seemed to her that her father's evasion meant 'yes.'

Eli rose from his bed and got to his feet. Azian was now sitting up. Her expression of weariness now softened into one of concern now that she observed the dark rings under her husband's eyes and his exhausted aspect. She knew it was the experiment with the anti-mass spectrometer that had been keeping Eli awake and anxious. Everyone, even those working and living outside of Sector C, had heard of it. Little was known either of the origin or composition of the mysterious crystal, though a great scientific breakthrough was expected.

Azian tried to console her husband while watching him get dressed. 'It's going to be fine honey,' she said. 'For all Dr Breen knows the spectrometer might not affect the crystal at all, and by this evening you'll feel silly for worrying about the experiment even a little.'

Eli nodded his head wearily.

Azian continued: 'Besides, it's not as if you're the one they're sending into the test chamber. You told me they're sending in the new man, whatever his name was.'

'Gordon Freeman. He volunteered to be the one wearing the HEV suit.'

'Right. So why are you so restless? Did you even sleep last night?'

'A little, I think.'

'By the time you come back to our dormitories this evening, you'll feel a weight has been lifted. You'll forget all about this experiment and you'll go back to worrying about more quotidian problems.'

Eli wanted to see the sense in what his wife was saying. What she had just said had been prudent and she was probably right, but something about how little was known about this experiment bothered him.

Like nearly everyone at Black Mesa, the Anomalous Materials staff were supposed to be scientists. It was their business to inquire about the truth of things, to understand reality at its most fundamental level. Yet there was so much about this experiment that remained ambiguous. Eli blamed Dr Breen. It was clear he knew more than he wanted to let on to his subordinates. And what of the man with the briefcase? He was a true mystery. Where on earth had he acquired the sample?

All these niggling doubts were compounded by the bizarre dreams he had been having. He couldn't have guessed how the two were connected. Eli tried to take succour in the fact that his wife was correct: It wouldn't be him in the test chamber. He would be by the computers with Izzy the whole time.

The family of three had breakfast together. Eli listened to Alyx babble about her future mechanical pet, how she would help her dad build it and about all the incredible things it could do. Eli listened half-heartedly, trying to take comfort in the enthusiasm and optimism of his lively daughter.

On most mornings, Eli would have more time with his wife and daughter, but today he had to leave early. A little later, Azian would take Alyx to Black Mesa's elementary school, an institution reserved for the children of the facility's resident scientists.

Leaving Black Mesa's dormitories, Eli joined a cluster of scientists gathered at the stop for the Transit System. Like him, they were all early. Unlike him, they were excited and hopeful about the upcoming experiment. Eli felt alienated and did not join in the conversation with his colleagues.

Only after a minute of waiting did Eli hear the familiar, timorous voice of his friend.

'Eli!' exclaimed Isaac Kleiner. 'Good to see you.'

'Morning Izzy.'

Kleiner had arrived just in time. The tram passed through the thick steel doors in the cavernous space the scientists found themselves in and was approaching its stop.

The balding scientist sidled up to Eli, his hands wringing. It was quite clear that Kleiner was just as anxious as Eli, though Eli was doing a better job of hiding it.

'Where's your man?' asked Eli. 'I thought he would be here early. So much depends on him.'

'You mean Gordon? Indeed. I expected to have found him right here at this stop. It's possible he has headed in early to prepare for the test, though it's equally possible he's running late. You can never be sure with that man. I daresay that if he doesn't turn up on time someone else will have to don that hazard suit in his stead.'

'I've spoken to Dr Breen', said Eli with a mischievous grin. 'I've volunteered you for the job if Gordon doesn't appear. You're more than qualified.'

Kleiner's complexion blanched to the colour of curdled milk.

'I do hope you're joking, Eli.'

'Of course, Izzy. I'm sure Gordon will make it. Those monitoring the test chamber will surely wait for him. It's not as if anyone really wants to take his place.'

Now the gaggle of physicists working in Sector C filed into the tram, almost filling it. Eli and Isaac, being at the back of the queue, did not get a place to sit, and thus remained standing for the short journey.

Good morning and welcome to the Black Mesa Transit System. This automated train is provided for the security and convenience of the Black Mesa research facility personnel. The time is 8:30 AM. Current topside temperature is 93F…

Eli and Dr Kleiner, as well as every other scientist who used the transit system, had heard the announcement more times than they could count and had learned to tune it out. The small group passed through the capacious environments of Black Mesa. Looking out of the tram, Eli could marvel at robotic arms piecing together machines unknown, large crates being moved along rails, large horizontal rockets, and finally the red rock cliffs of Black Mesa's surface.

…Please keep your limbs inside the train at all times. Do not attempt to open the doors until the train has come to a complete halt at the station platform…

Eli could not put his fears and last night's nightmares out of his mind. He knew he felt the same about today's big event as Kleiner did.

'Have you been thinking about the experiment, Izzy?'

His friend nodded. 'How could I not. Today's test could make or break our careers. If Black Mesa wasn't under such security restrictions the whole world would know about what we're about to do down here. We would become quite notable, at least in the scientific community.'

Eli grinned. 'You would know all about being notable in the scientific community, Izzy. We've all seen you on the cover of Popular Scientist.'

Kleiner shifted on his feet uncomfortably. It was true that he had been something of a celebrity in his MIT days, especially since the advent of his book From Here to There in Under a Second.

Isaac let out an uneasy cough. 'You know I never had any interest in notoriety, Eli, and those days are over now. I am quite glad of it. The brief taste I had of being at the 'Next Level of Quantum Physics' was quite enough. Now I can focus solely on my work here at this facility.'

Eli steered the subject back towards the test. 'You'll probably find this ridiculous, Izzy, but I've been having nightmares about today's big event.'

'Really?'

'Yes. Strange dreams.'

'Strange? In what way?'

'What look like alien worlds. Nothing like anything I've seen in real life. The only thing I can recognise in them from reality was the pale man with the briefcase. He features in the dreams too. You've seen him yourself?'

'Everyone in Anomalous Materials has seen him, Eli. He is quite the mystery, and odd-looking too. I have never spoken to him.'

'Nor I. I have seen Breen talking to him though. It was in one of the partitioned office from behind a pane of glass. All the other times I have seen him alone, wandering around, as if giving himself a tour of our facility.'

'Most odd.'

'Do you think he has something to do with the sample for the experiment?'

'I heard a rumour', Isaac began, 'that the man with the briefcase is the one who provided the exotic matter crystal. After all, the man and the object did appear at the same time. I'd wager Breen would know the truth. Much more of it than he's been letting on at least.'

'And you', Eli said. 'Have you been getting any strange premonitions about this test?'

'Nothing further than my usual apprehension, Eli. But that is no rare thing, I'm afraid.'

Eli sunk into a sombre silence. They were approaching Anomalous Materials now. Some massive circular doors pulled themselves open, it seemed, with great labour. Everything at Black Mesa appeared to be heavily secured and confined. The scientists surrounding Eli and Isaac had not stopped chatting excitedly. Only the two friends seemed not to be so buoyant.

In a moment, the tram came to a stop.

Now arriving at Sector C Test Labs and Control Facilities. Please stand back from the automated door and wait for the security officer to verify your identity. Before exiting the train, be sure to check your area for personal belongings. Thank you, and have a very safe and productive day.

The security guard seemed to be taking his time on the platform between the tram and Sector C's entrance. When he did approach the tram, he entered a code into the keypad to the right of the door and it slid open.

'Mornin' doctors', he said. 'Big day for you fellas, huh.'

One of the scientists said to a colleague: 'See. Even the security force have heard of what's happening today. And they say what goes on in this facility is meant to be top secret.'

The physicists filed out of the carriage, the steel grating of the platform rattling under their feet. Eli and Kleiner followed and the small group approached the entrance. The security guard entered another pin-code into the panel to the left of it, and the door's two huge bars moved aside, the two vertical halves of the door, like a gaping metal maw, hauled themselves open.

After this there was a similar door, and then the space opened up into the Anomalous Materials lobby, around which milled about a couple of scientists in laboratory coats and a security guard at the desk. He waved the crowd of employees through. Dr. Kleiner approached the desk.

'Excuse me', he ventured. 'Has Dr. Gordon Freeman by any chance passed through here already?'

'I'm afraid not, doctor.'

'So I was right', said Dr. Kleiner to Eli. 'He is running late. The experiment cannot go ahead without him. He'd better hurry.'

He turned back to the guard.

'Could you please tell him not to forget to put on his hazard suit before heading down to the test chamber?'

'Will do, Doc.'

Eli and Isaac ambled toward personnel facilities. Approaching the miniature cafeteria, Dr. Kleiner poked his head in to see Arne Magnusson, the most cantankerous of their colleagues, preparing a casserole to be heated in the microwave. Kleiner wanted to enter the space and take something from the vending machine before the experiment began, but thought better of it. He avoided Magnusson wherever possible. The two of them had a long history of competition for great money, something which seemed to make Magnusson especially spiteful to Kleiner, though it was hard to tell for sure. Arne Magnusson was rarely cordial to anyone.

Eli and Kleiner now headed down to the locker room. Like nearly everywhere in Black Mesa, it was quite spacious. The two physicists donned their laboratory coats from their respective lockers, then gave the HEV suit compartment a brief look. As expected, there was one extra hazard suit standing unused. Where the other two were, they couldn't have said, but the remaining one was destined to be occupied by Gordon Freeman.

It was time they took up their places by the computers, not far from the anti-mass spectrometer chamber. Their path there, like much of Black Mesa, was long, sterile, and winding. They passed several doors which were opened for them by security guards once they had flashed their IDs at them. Next they took one of the facilities famously slow elevators, but the distance was not great from there, and soon they found themselves on the observation deck which looked down into the test chamber. There were already two of their colleagues seated there, like them, in laboratory coats. One spoke up upon their entry:

'Have either of you seen Gordon Freeman?' he asked.

'I'm afraid not, Dr. Guthrie. But never fear, I'm sure he'll be along in just a moment.'

'Fifteen minutes late on the day of our great experiment. It's deplorable. You're the one who recommended him, Kleiner. He was your understudy at MIT. I hope his delay doesn't reflect his competence.'

'Gordon is quite capable, Guthrie, quite capable indeed. I'm sure there must be a reasonable explanation for his tardiness. He'll be here any second now. He is surely donning the hazard suit as we speak.'

Eli said: 'I'm going to wait by the data processor a little ahead, Izzy. You can escort Gordon in when he does arrive.'

As Eli approached the sliding door, the scientists in the observation deck changed their topic of conversation to the task at hand.

'We should send the sample down to the test chamber', suggested Dr. Backman, who had not yet spoken.

'Yes, posthaste', said Guthrie. 'Before you arrived, Kleiner, we decided to boost the anti-mass spectrometer to 105%. We realise its a gamble, but we need the extra resolution…'

Eli left the deck. What Guthrie had been saying bothered him. He had been anxious enough about the experiment without his colleague making constant changes to the forthcoming test. Eli was now in the room he was most familiar with at Black Mesa, aside from his family's dormitories. There were three, miniature, fluorescent portals behind the glass of large jars near the wall on his right. On the left were several mainframe computers behind glass. Eli walked to the one in the far corner which he could operate. Just as he approached it, the door behind him slid open.

'Eli, look who is finally here', said Isaac Kleiner.

Eli turned to see his friend, and Gordon Freeman just behind him.

'Gordon!' exclaimed Eli. 'Good morning.'

Their younger colleague stood out like a sore thumb in the bulky, orange and grey hazard suit he was wearing. As was often the case, he bore a strange smile on his face. Despite the fact that Freeman was reticent almost to the point of speechlessness, most sensed a certain charisma he had and he was liked by many.

Eli turned to Dr. Kleiner to voice his concerns. 'I'm glad you're here. These last minute changes, they're a bit strange to just—'

Suddenly, from behind him, Eli heard a great crack. Their computer accoutrements seemed to have started malfunctioning. Sparks flew and electricity discharged from one part of the apparatus to another. Eli rushed over to it and began to do his best to locate the source of the problem.

'What in the blazes is going on with our equipment?' proclaimed Kleiner.

Turning back to his colleagues, Eli let out an apprehensive sigh. 'It was never meant to do this in the first place.'

Kleiner said: 'It's nothing we can't handle ourselves, Eli.' His tone was uncharacteristically self-assured. 'Run along, Gordon', he continued. 'We'll be but a moment.'

Dr. Freeman nodded and turned, making his way to the elevator opposite the equipment which had just malfunctioned. Gordon stepped in, and the elevator revolved anti-clockwise, bearing him downward.

Eli turned back to the problem at hand. Thing were going from bad to worse. His faint hope that the experiment with the crystal would go smoothly and without mishap, the hope that Azian had expressed to him that morning, now seemed to be slipping away.

'It's the anti-mass spectrometer', said Kleiner. 'Guthrie said that he boosted it to 105% for extra resolution. Our computers cannot take the strain.'

'Our colleagues are so eager to see the results that the crystal will yield that they're throwing caution completely to the wind. I just hope Gordon will be okay down there. I wouldn't want to be the one in the test chamber.'

'Nor I', said Kleiner.

'Come on', said Eli. 'Let's try and do what we can with the mainframe. We've come too far to stop now. I bet if we asked Backman and Guthrie to abort the test they'd just shout at us to get back to our posts.'

'Indeed, Eli', said Kleiner concernedly. 'Oh fie. I do hope the test transpires without mishap.'

'So do I.'

Eli was about to turn his attention back to the data processor which was still on the fritz, when he got the strange feeling that someone else was standing behind him. Someone who was not Dr. Kleiner. Before he could turn around, he heard a rattling, unearthly breath behind him, and into his ear a preternatural voice whispered:

'Prepare for unforeseen consequences.'

With a start, Eli jolted around, finding the space to be empty but for him and Dr. Kleiner.

'Did you say something, Izzy?'

Kleiner looked at him curiously. 'No, Eli, not a word.'

It took Eli a moment to settle his nerves, feelings of dread weighing heavy on his heart. He sighed and resumed work on the malfunctioning machine.