Chapter One

1533 hours, February 22, 2554 (military calendar)

Underground thoroughfare

Forerunner storage facility, Installation 03, Khaphrae System

The passage looked like it went on forever to Spartan Tom Ryan, though he had to wonder if tunnel wasn't a better description. Two Scorpion tanks could have travelled down it side by side with room to spare beneath a vaulted ceiling that rose nearly thirty metres above him, built in the trapezoidal style ubiquitous of the Forerunners and constructed from the same silvery-grey metal that was impervious to everything but the heaviest of starship weapons.

It was an immense space that easily absorbed all sound, including the thuds of Ryan's booted feet as he walked along the passage and those of an ONI research team he was assigned to protect. Their conversations seemed muted too, though that could have been because of the hushed, almost reverent tones being used as they discussed their surroundings which struck Ryan as odd, even taking into account the fact they were on a Halo.

He felt that way because, despite the grandiose and immense appearance of their surroundings, the team was essentially walking through the Forerunner equivalent to a depot or garage, albeit one that was empty. Every 350 metres or so were giant sets of blast doors as tall as the ceiling itself, and beyond them were even more passages that vanished into the distance. Lining these passages were smaller doors that led into rooms fifty meters to a side, except they had nothing in them. No weapons, no suits of armour, not even a vehicle that the team could have used to speed up their exploration of the elaborate underground facility.

They hadn't even found any dust.

Regardless, the five-person team retained their enthusiasm in spite of the lack of artefacts and pressed on, stopping occasionally at a random door to see if their luck might change but it never did. It was just row after row of empty rooms lining tunnels that seemed to stretch on into infinity, telling Ryan that whatever plans the Forerunners might have had for their seven, now six rings never fully came to fruition, with this incalculable number of empty rooms being all that remained.

He sighed inwardly as the researchers keyed open another door to reveal another passageway and checked his mission clock, wincing on seeing they had been down here in the tunnel for almost three hours by now with nothing really to show for it other than worn shoe leather.

'Should we maybe start to think about turning back?' he said aloud, causing some of the researchers to look his way. 'I don't think we're going to find anything down here.'

But one of the researchers, Eddie, shook his head and said, 'Not for another hour, Spartan. Besides, if needs be, we can make camp down here.'

Each of the team had their own equivalent to a three-day assault pack on their shoulders, carrying enough food, water and other consumables to keep them going for two or three days without needing external resupply, including sleeping bags, meaning they could theoretically spend almost a full 72 hours below the surface of Gamma Halo. That wasn't the reason they carried them though. More, it was because most Forerunner sites were notorious for having slipspace portals spread throughout them, and for them being at times impossible to spot even when operational.

It wasn't unheard of for unaware research teams to wander into one and find themselves hundreds, if not thousands of miles from where they had been with no easy way to return to base. Having the packs meant the chances of them being recovered alive in such a situation were significantly higher than they would have been otherwise, not so they could spend literal days underground combing through what was very obviously an empty storage depot.

Of course, their three-day endurance paled in comparison to Ryan's weeks long duration, thanks mostly in part to the myriad of soft cases attached to his NOBLE-class Mjolnir armour and the various other functions it offered, but that was beside the point. They hadn't found anything of any real value and that wasn't likely to change regardless of how long they stayed down here.

Unfortunately for Ryan that wasn't his call to make. His role on the team was security, so unless something presented itself as a direct threat to them he was effectively along for the ride until such a time they decided to return to the surface. That and serving as host for Artoria, an AI tasked with interfacing with any Forerunner networks they came across though like the Spartan carrying her she had yet to fulfil her intended purpose.

He let out another sigh and glanced back the way they had come, to an elevator some eleven kilometres away that four hours ago had dropped them down through who knew how many layers of Gamma Halo into the storage facility. They hadn't even been looking for anything in particular, just exploring for the sake of exploration and taken the elevator on a whim. Now they were thinking of spending the night down here!

At least, Eddie was thinking of doing that but judging by the fact nobody else spoke up in opposition to the notion told Ryan they were open to the idea. And again, he could only question why they were choosing to expend so much time down here when nothing at all had been discovered. They hadn't even caught a single hint any Sentinels were down here, or any of the other automated drones the Forerunners used to keep their various installations operational.

Ryan had no idea if that was good or not, or if the vast bulk of the robotic workers had been diverted to handle some as yet unknown crisis elsewhere on the ring. Briefly his mind flashed to the Flood, the alien parasite Halo had originally been designed to counter and kill, and house, strangely enough, in vast underground facilities, but he quickly banished it from conscious thought. Though most Halos did house specimens of the alien parasite somewhere on them, such facilities were located in either thick swamps or a frozen tundra. To hide them and slow any potential outbreaks respectively, whereas the entrance in this tunnel had been in the middle of a dense rainforest, inside a plain looking temple.

Even so, as the promised hour came and went with the research team showing no signs of stopping, Ryan began to hope for at least some measure of excitement or just something that would convince the researchers to call an end to their pointless exploration of the empty rooms and begin heading back to the surface, which is exactly what he got.

By the time his mission clock read it was almost five in the evening, a shout went up from one of the researchers about another door ahead of them, though unlike the gargantuan blast doors they had walked past this one was of a more reasonable size, no more than ten feet high, and the passageway it opened up into was wreathed in complete darkness. Neither did it appear to have any other doors branching off from it, though the absolute darkness within made discerning anything beyond the immediate doorway a challenge.

As one, and without a word passed between them, the researchers pulled out various sources of illumination that were snapped on to beat back the darkness before filing in with Ryan doing the same moments later, taking the time to give them all an exasperated stare from behind his visor.

'Of course they charged into a dark corridor without a second thought,' Ryan muttered as he caught up with the team. 'Why wouldn't they?'

'The allure of knowledge can be a strong motivator, Sir Spartan,' Artoria said in her clipped, almost archaic British accent. 'This tunnel is an outlier to what they have been seeing since arriving. Why would they not choose to investigate further?'

'Because it's dark and cramped, compared to before,' Ryan said. 'That's never a good sign. Especially not on a Halo.'

Again, his thoughts briefly turned to the Flood but Ryan managed to resist the urge to draw his MA5K carbine and assume point, though he did say, 'And how far into this tunnel are you planning on going?'

'More than a few minutes,' Eddie said from somewhere up ahead of him. 'You'll know when we turn back.'

That seemed to be the end of the conversation as far as Eddie was concerned, he and the other researchers dropping back into quietly discussing their surroundings and positing theories as to just what it was they were in or where it might lead, or why it was in total darkness. Back in the main corridor, lighting had been provided by a number of recessed strips in both the floor and walls. Here, though, there was nothing beyond the occasional Forerunner glyph or sigil. More than that, they pointed out, the walls were showing signs of tarnishing. Their usual silver-grey colour was slowly giving way to a more corroded brown, suggesting maintenance of this corridor was low on the list of jobs for Gamma Halo's caretakers.

That, in turn, gave rise to the question of why considering the pristine state of a much larger passageway just outside, plus all the other rooms and tunnels that branched off the main one, but soon enough all questions and even chatter ceased when raspy moans could be heard coming from somewhere ahead of them. They froze as one and pointed all their lights in the direction of the noise but whatever it was wasn't close enough to be illuminated, though judging by the pitter-patter of bare feet on metal there was a good chance it had seen the lights in the distance and was coming to investigate.

Ryan drew his MA5K as he strode forward to put himself between the research team and whatever it was heading their way, the sound of running feet slowly resolving into several distinct sets of five, maybe six creatures letting out a mixture of rasping moans and the occasional high pitched shriek that once again conjured up thoughts of it being the Flood and for a brief moment, when they finally came close enough to see, Ryan felt his worst fears had come true.

Each humanoid bore a striking resemblance to a corpse given the lack of flesh and were gibbering like Flood forms did during combat. That was where the similarities ended though, as none of the six humanoids running towards him had tentacles anywhere on their bodies and neither did Ryan see the quivering feelers typical of the infection form that normally took up position inside the chest cavity, or any of the other horrific changes done to a body when infected.

If anything, these humanoids bore a striking resemblance to regular humans that had died of their own accord, and then been left to rot long enough for the outer layers of skin to slough off and reveal the musculature beneath, plus the occasional rib, before somehow having life breathed back into them as they were. In a way they reminded Ryan of zombies from cheesy horror movies one of his fellow Spartan-IV recruits had shown him during training, both in appearance and behaviour seeing as they were rushing towards him with hands outstretched. Whatever they were, and whoever they might have been, that marked them as hostile and freed him up to engage.

He levelled his carbine at the nearest figure and fired a short burst dead centre mass, sending it sprawling to the floor though if the others noticed or cared, they didn't show it and continued to charge the team and their Spartan escort, shrieking all the while, but Ryan's fire was too accurate and they proved to be remarkably fragile. One or two bursts was often all it took to drop them, maybe not even that, and as quickly as the humanoids had appeared they were lying dead on the floor in a haphazard pile.

Ryan ejected his nearly spent magazine and reloaded as he strained his ears to pick up the sounds of any other humanoids that might be coming their way, but there was nothing beyond the stifled, almost panicked breathing of the researchers behind him. Once a minute of this had passed he lowered his carbine and turned to face the team, asking, 'Everyone okay?'

It seemed to jolt them back to some measure of awareness and they were quick to check one another for anything wrong, the worst any of them had experienced being a pale complexion from shock and fright. Satisfied, Ryan gave a nod of the head then started moving towards the humanoids to try and figure what they were if not the Flood. That, and to place a round in the head of each to make doubly sure they were dead.

He knelt by the first and flipped it over so it was face up, but the moment his gloves touched the thing an alert popped up on his HUD about an elevated radiation count coming from the creature.

'Stay back,' Ryan said as he held a warning hand out to the researchers that had followed him. 'This thing is hot.'

'As in radioactive?' one of the researchers said, getting a nod in response. 'What is it?'

'I think it's a human,' Ryan said. 'Or at least it was.'

It had all the right limbs in roughly the right proportions and locations, each of them terminating in the usual five digits or had a space for them at least, and a face that had two eyes and a mouth full of rotten teeth right where a normal human would but anything that might resemble lips, a nose or eyelids was missing though considering the decayed state of the entire body, they might have simply rotted off along with the rest of the soft tissues. The creatures were about the right height, too, and any weight discrepancies could be explained away by the fact they were basically a walking corpse.

Examinations of the other five creatures produced nothing new beyond a locket partially fused into the flesh of one, a badly tarnished and corroded thing that only had the words -ing Daisy eligible on any part of it, plus a smattering of bottlecaps for some brand called Nuka-Cola. Ryan had never heard of it but given there were several hundred colonies across human controlled space, chances were good it was a local flavour on a colony he hadn't visited yet.

Either way, between them and the locket, it stood to very good reason that these decayed things had indeed been human once which then posed the questions of; what it was that had turned them into such a state, and how had they then wound up deep in the bowels of Gamma Halo? For a brief moment Ryan toyed with the idea that ONI had tested some new CBRN weapon, only to dismiss it almost as quickly.

As morally ambiguous as the shadowy intelligence agency was, they also weren't stupid enough to test such a thing on a superweapon capable of eliminating all life in the universe. If something were to go wrong they risked losing control of Gamma Halo, or exposing their highly illegal experimentations once reinforcements arrived. Better, then, to carry out their nefarious schemes on some distant planet only they knew of.

'Ain't no way that was human,' Eddie said as looked past Ryan at the corpses. 'I should know. I am one.'

'All evidence points to them being exactly that,' Ryan said.

He stood and drew his carbine again but looked down the passageway towards where the decayed humans had come from. Their next step would be to return to the surface and report what they had found so that a more proper investigation could be mounted, part of which would involve securing the site. Ryan had no idea how many more of these creatures there were or even how much further into the tunnel they might be. They had only gone a few hundred metres before encountering the creatures whilst the passage extended beyond even Ryan's augmented sight, stretching who knew how many kilometres into the ring.

This small group might be only but a fraction of the walking corpses awaiting the research teams and their security escort, plus who knew how many other horrors, meaning finding out for certain wouldn't be a bad idea.

'Start heading back to the surface,' Ryan said. 'I'll catch up once I know where our new friends came from.'

1827 hours, February 22, 2554 (military calendar)

Underground tunnel

Forerunner storage facility, Installation 03, Khaphrae System

For the past hour Ryan had maintained a steady jog which, by Spartan standards, was close to twenty-four kilometres an hour but in all that time, the tunnel he was in hadn't changed a single iota. Its unlit walls remained the same decayed brown whilst the corridor itself ran straight and true, never once veering to the left or right, up or down, just straight ahead. Neither did it appear to contain any more of the decayed humans or anything that might have caused them, just kilometre after kilometre of nothing to the point he was considering turning back.

There was no telling how long they might have been down here or how far they could have travelled, and with the ring itself being almost 320 kilometres wide it was entirely possible they could have come from the far side. Ryan began to slow down a little then came to a complete stop once he heard the crunch of dirt beneath his boot, looking down to see the beginnings of a layer of sand on the floor which he took to be a good sign.

Elsewhere on the ring, the internal surfaces were totally free of any dirt or dust despite their size and lack of a noticeable custodial complement. The same had held true down here even in this tunnel, despite its otherwise shabby appearance, meaning whatever was behind the transformation of those people was close. Either the device itself or an open portal to wherever it was stored, with the sand blowing in.

He knelt and ran a hand through the sand, getting the same alert on his HUD about elevated radiation levels as he had from examining the decayed humans, then on looking up he saw a very faint glimmer of light in the far distance. It wasn't exactly shining brightly but against a backdrop of pitch blackness, it might have well been so he stood once again and resumed his jog.

1900 hours, February 22, 2554 (military calendar)

Underground tunnel

Unknown location

At some point during his run towards the light Ryan found himself passing through what could have only been a slipspace portal, the transition of which was so smooth it had taken him a moment or several to register that the metal walls had given way to roughly hewn rock and that there was now hardpacked dirt beneath his feet. He came to an abrupt stop when he realised it and raised his carbine into a firing position, ready for anything that might come for him, but there was nothing. Just dirt and rock.

If anything the most pressing concern was when he turned around to look for the portal, only to see in place of a Forerunner tunnel was a cave maybe thirty metres across and empty, beyond a few rocky outcroppings and one or two stalactites. He took a few paces towards it in the hopes he was looking at some kind of security illusion but the tunnel didn't reappear, remaining a gloomy cave whose back wall was solid to the touch.

'That's a problem,' Ryan said.

'So it would seem, Sir Spartan,' Artoria said. 'However, scans show the environment to be suitable for sustaining life. Atmosphere and gravity readings show Earth-norm, with the only major issue being an elevated background radiation count. Though, thankfully, it is nowhere near what could be considered life threatening for extended periods of time, doubly so given your protective garb.'

Ryan cast a quick glance at his Mjolnir armour as he turned away from the cave and returned his attention to the distant light at the end of the tunnel, saying, 'That's comforting to know. I'd feel better knowing where we are, though.'

'As would I, Sir Spartan,' Artoria said.

The tunnel ran for another hundred metres, gradually widening out the closer it got to the entrance, and it was there that Ryan got his first sign of human life, albeit in the form of a skeleton curled up behind a two-door coupe. Both looked like they had been there for a good long while, the body devoid of any scraps of flesh whilst the vehicle was completely rusted over, with the only things that looked to have survived however long it had been being a pair of leather boots and a wide brimmed hat. Even then they were in poor condition and of no use to anyone.

'Male,' Artoria said as Ryan knelt to examine the corpse. 'Early twenties, at best, with no obvious signs of death. I would surmise that he came here seeking shelter, only to expire of thirst or starvation.'

'Works for me,' Ryan said.

He gave the car a quick look but it wasn't a design or model he was familiar with, and as with the Nuka-Cola brand from earlier he classed it as being a local development that hadn't yet reached the wider sphere of human influence. At the very least, the skeleton and car meant he was on a world humanity had colonised which meant there was a decent chance it had a line of communication back to Earth, and eventually a ride off it and back to either Gamma Halo or wherever his superiors felt his talents could be put to best use.

Worst case, though, was that this colony had been hit by the Covenant years ago and was abandoned, with the elevated background radiation being a byproduct of an extensive campaign of nuclear bombardment to remove the alien menace. Then there was the issue surrounding the disfigured humans he had encountered in the depths of Gamma Halo. How had they come into being?

Thinking of them prompted Ryan to draw his MA5K again, wary of any that might be nearby, slowly making his way to the mouth of the cave where he was treated to his first view of this world, whatever or wherever it might be. Before him and spreading all the way to the distant horizon was an endless expanse of blasted desert badlands, pockmarked here and there with rocky outcroppings or scrub brush, even what looked to be the remains of buildings, all of this beneath a deep blue sky though judging by where the local star was and a growing band of orange and purple hues around it evening wasn't too far off.

It was silent, too, the only thing Ryan could hear being the gentle blowing of wind and the rustling of some nearby bushes swaying in it. Strangely, he felt a sense of tranquillity as he took it all in. This, despite the fact he could well be the only living being on this planet and, depending on how thorough the Covenant had been, trapped without a means of telling anyone where he was.

That was a long term problem though, and arguably Ryan had all the time he needed to sort things out. His suit carried two or three weeks of supplies, during which he would have ample opportunity to find either a cache of leftover provisions in some of the ruined buildings or see what kind of animals or plants were still around. Plus, if push came to shove, he could eat parts of the bushes he had seen thanks to his augmentations though that was an absolute last resort.

He spent the next hour scouting the area around the cave which, for the time being, would be his home before perching himself on a rock located just above the mouth it as the sun began setting, the horizon becoming a wash of orange, pink and yellow hues that slowly gave way to a uniform black as night finally fell upon the planet. More importantly, the various stars came out which would allow Artoria a chance to determine where they were thanks to her collection of astronavigation charts.

Ryan waited as he looked up at the distant twinkling lights, lines flashing across his HUD as Artoria examined the brighter points and apparent constellations against her database for what seemed like an age. When she was done though, and came back with her result, he had her run the check again and again several times over because what she was telling him was impossible.

According to Artoria, they were on humanity's homeworld. They were on Earth.