Jack's paranoia was reaching a boiling point.

The doorway they'd found had led them to a tunnel. It wasn't very big, it wasn't very threatening, and their flashlights provided enough light to see by. There were no surprises. There were no demons. There were no hiding spaces.

It was just a simple, straightforward tunnel of generic rock.

It was really starting to get to him.

No one spoke and they received no contact of any kind, which didn't surprise him. Jack had no idea how deep underground they were at this point. He didn't even understand why this tunnel was here. Only that it was in the general direction they needed to, which was truly all that mattered in the moment.

They had to get to their destination.

They had managed to get themselves to within half a mile of their destination when the tunnel finally ran out, terminating abruptly in a simple steel silver door. It was so normal-looking, so bland, so like the generic doors that he'd gotten used to seeing on Mars that it only heightened his paranoia. Jack took a deep breath and let it out slowly, willing himself, his body, his mind, to relax. They weren't done yet, and he couldn't afford to snap.

Way too much was counting on them.

"I've got a door here. Going to open it. Everyone fall back a bit," he said.

They responded affirmatively and fell back a few meters. Jack stared unhappily at the little button beside it, built into the silver frame.

He pushed the button.

There was light beyond, a strange mixture of white light from brilliant halogens stacked up on either side immediately beyond the door in columns of rectangular luminescence for some reason, and the murky green glow of toxic gunk. Double-barrel at the ready, Jack slowly edged forward onto a simple concrete platform. A basic room awaited him beyond, barely six feet across and six high. The walls to either side were iron slabs studded with bolts, the roof a rough green rock similar to that of the tunnel they'd been walking through, and ahead of him opened up into a much larger, broader room. The stone floor narrowed into a pathway that continued dead ahead, and to either side of it lay bubbling pools of toxic waste.

Like lava on Saint Patrick's Day.

The stone path that led through the sludge opened into another room maybe twenty feet away. As Jack stepped up to the edge of the tiny area he was in now, he immediately heard several warning roars and hisses, and then fireballs were coming his way from the left and right, high up. There were iron bar sections among the plating, and behind each he saw the shadowy figures of Imps. And they were chucking fireballs like there was no tomorrow.

"Someone get up here, we got Imps to clean out!" Jack called.

Cortez joined him and each of them picked a side, using the walls as cover. It didn't take long to cap all the Imps that revealed themselves up in the strange chambers. Jack wondered why this room had even been built, what they were doing up there, what the purpose of this place was, but that train of thought quickly derailed. None of this made any kind of sense, it just was. It was all just another place for them to kill their way through.

Once they finished off the Imps, Jack reloaded and looked around.

"Cortez, with me. We'll scout ahead, everyone wait here," he said, and set off.

The pair of Marines walked slowly along the stone pathway, wary of any further dangers. Jack was ready for a Baron to drop down from somewhere, for the path to drop down from beneath his feet, for a tidal wave of toxic sludge to cascade down onto him. But nothing happened as they reached the next room. Several ways out and potential paths awaited his inspection. Dead ahead was a short corridor that ended in one of those tall tech-studded doors. It came complete with not just more of those racked halogens, but a pair of brass torch-holders that burned with wavering red-yellow fire. To either side of him was a stairwell that led up to a caged room. To his right was a dead-end that seemed to hold nothing, save for a single severed leg, complete with Marine fatigues and regulation combat boot, hanging upside-down from a chain in the ceiling, slowly dripping blood.

And finally, to his left, was another short alcove that opened up into a large, cavernous room made entirely of cracked sandstone, save for a jagged, crooked, narrow pathway of white-gray stonework that led perilously across it to a little chamber that held...something red.

Jack heaved a sigh as he and Cortez looked at that.

"How much you wanna bet that's a keycard we need?" he muttered.

"Not taking that bet," Cortez replied. "The left stairwell leads up to a door with red trim."

"Of course it does. All right." Jack went back to the way they'd first come in and waved the others over, giving the all-clear. They joined him in the main room and began moving around to further secure the area. Jack considered his next course of action for a moment, and finally decided to just get the red keycard and get it over with.

"Abrash, Cortez, I want you standing right here," he said, indicating the head of the path, "covering my ass. Anything pops up, or drops in, or teleports in, or what the fuck ever, you blast the fuckers fast as shit, all right?"

"You got it, Sergeant," Cortez replied, and Abrash nodded tightly, both of them hefting their respective weapons.

Jack stepped up to the pathway and looked around. To either side of the narrow path was a twenty foot drop...straight into more of that bubbling green crap. He sighed heavily. Why did he had to do shit like this? He supposed he could order someone else to do it, and they would, but it somehow felt wrong. It felt like this was his responsibility. Was it about proving himself? No, it couldn't be. He'd proven himself a thousand times over since this whole shitstorm began. Maybe it was just a sense of duty. This was his burden to bear.

Focusing himself, Jack switched to the plasma rifle, because if he was going to get attacked, then whatever it was would need to die, and quickly, and stepped out onto the path. It wasn't just that it was narrow. No, that wouldn't be enough, would it? It was narrow and strangely jagged, crooked. Hell, he half expected it to just fall over as he stepped onto it.

But it held. And nothing happened as he started his walk. He kept his pace slow but steady, stealing little glances everywhere he could, but still nothing happened. It was like the world was holding its breath, waiting to spring the trap on him.

Jack finished navigating the crooked path and stepped onto the narrow area of space built into the wall at its end. He ducked down, scooped up the red keycard, and pocketed it as he stood back up. Now to get back over without-

The wall at the back of the narrow niche abruptly opened up, revealing more iron bars. Behind those bars a trio of Imps screamed at him.

"Fuck!" Jack roared, snapping the plasma rifle up and hosing them down without fully realizing he'd done so. They burned and fried, their leathery skin crisping and flaying off under the barrage of the superheated plasma balls.

They died shrieking, and that should've been the end of it.

Only it wasn't. Before he could fully turn around, Jack heard a chaingun spin up and then felt a barrage of bullets start punching into his armor and rain in a hail of metal death all around him. Cursing, he spun around and leaped to the side, barely avoiding falling over the edge of the narrow space. Back across the room, to his right, another panel in the wall had sprung open, revealing a Chaingunner.

It was, of course, just beyond the view of Abrash and Cortez, who seemed to be focusing on something else that he couldn't see. Aiming the rifle once more, he fired off a barrage, emptying the power cell currently in the weapon. It did the trick, frying the Chaingunner's face and melting off one of its arms, but as he reloaded, something else happened.

Abrash and Cortez both opened fire on something out of his line of sight to his left. He heard a familiar hissing shriek and then suddenly there was a loud pop and some guts flew by the niche. "You're clear! Come on!" Abrash called.

Jack decided now or never and began making his return. A glimpse down into the muck told him that they'd popped a Cacodemon and now it was dissolving down there. Good. He fucking hated those grinning bastards. Well, he hated them all.

He almost lost his balance near the end and for a gut-wrenching second came perilously close to going over the edge, but then he caught himself and hurried the rest of the way, finally getting back on solid ground.

"Damn," Diaz said. "I saw that. You got a lotta guts."

"We all do," Jack muttered as he caught his breath. Too close. Definitely too close. "Come on, let's push on. I want out of this nightmare."

The stairs to the right led up to an empty room but the stairs to left held that door with the red trim, and a slot for the card. Jack inserted it and stepped inside, shotgun at the ready. Nothing waited for him in there but a big button and a view into the section beyond in the form of more iron bars instead of a traditional wall again.

"Holy crap," Vekovious whispered as he joined Jack in the room and looked through the bars.

Holy crap indeed. The way beyond wasn't what captivated them, strange though it was. No, the sky, which was now visible again, did.

The red beam of light that shot straight up was larger and more visible than ever. A strange crimson energy crackled out from it and it pulsed, thrummed with raw power.

The sky shook with it.

"How in the fuck are we gonna stop that?" Vekovious said softly.

"Bomb, hopefully," Jack replied. "But we'll worry about that when we get there."

"It's that easy for you?" Vekovious asked. "How does it not...overwhelm you?"

"Survival trait," Jack replied as he studied the immediate area that lay beyond. "I had to develop it over the course of my career, but it became a fucking superpower in hell. If I let myself think about everything that was happening...it was too much. Like now. So, don't. Just focus on right here, right now, and maybe a little beyond. Don't look at the big picture, if you can help it."

"I guess so."

The way ahead was a big, open courtyard that was again one big toxic acid pit. There was a pillar on a small island of stone in the center, and the walls along the courtyard's edge were made of both large bricks of stonework masonry and more iron plating. There were more cages in the walls, and he could hear groans and growls, though he couldn't see anything immediately threatening. He couldn't see any obvious way forward from up here that didn't require running through the acid. Just great. Exactly what he needed today.

"Okay, everyone get ready down there, I'm gonna push a button," Jack called.

"Ready!" Abrash replied a moment later.

Jack pushed the button. There was a loud click that made him jump, and he heard something happen, but he couldn't see anything. "Well?"

"The main door opened," Abrash reported.

"Understood."

He and Vekovious walked back down the stairs into the main room and approached the now open door. They all gathered at it, getting into defensive positions. Jack opened the door and stepped slowly out, assault rifle back in hand. There was indeed a pool of acid waiting for them out there, a square pool, the walls rising up a good forty feet around them. Still no demons attacking them, but they definitely sounded close.

"Looks like we've got no choice," Jack said after a moment longer of study. "Our suits should be able to handle it for short bursts. I can just see around that pillar in the center there, and I'm willing to bet that the door or bars or whatever the fuck it is opposite us now is the way out, since it's the only one that's blocked off. I see yellow trim, so...keep an eye out for a yellow keycard. I'm going to split us up. Abrash, take Vekovious, Diaz, and Spencer over to the right there. Cortez and I will handle the left."

"You gotta lotta faith in me, Sergeant," Cortez said with a laugh.

"I'm more just paranoid about that bomb. Make sure nothing happens to it," Jack replied. "Stay in radio contact, clear out the place, and find that keycard. I know we're all tired, and in pain, and stressed. But we're close. We gotta keep focused. Don't cut them any slack, because they won't cut you any. No shortcuts, no half-measures. Got it?" he asked, looking around at each of them slowly, one by one.

They all nodded, all responded with a firm 'Yes, Sergeant'.

"Good. Let's get it done."

They split up. The jog across the acid pit was harrowing but short, and their armor seemed to hold up pretty well when he and Cortez paused to inspect it after reaching a little platform that granted access to whatever the hell was beyond the left wall of this strange courtyard. Both men prepared themselves and then Jack opened the door dividing them from what lay beyond. And that turned out to be a small army of demons.

Half a dozen Imps, a clutch of zombies, and a brutish Chaingunner all roared in a symphony of inhuman hatred as they laid eyes on the two Marines and then the battle began. Each man used one side of the door as cover and hosed the room down. Cortez used his assault rifle, flipped to full auto, and Jack used his plasma gun. Together, they blasted through the roomful of monsters. Jack decapitated the Chaingunner first by sending a solid stream of blue-white plasma right into its face, burning its head right off its shoulders.

He watched as its chaingun started misfiring, swinging wildly about the room and catching two of the zombies in the process, who got pissed and started blasting away at the nearby Imps. Between everyone killing and blasting away, they cleared that room in record time, even with the dozen or so other Imps and zombies that were drawn in by the noise. As the fighting died down, they stepped in and took a look around.

The room was largely dominated by a raised section right in the middle, blocking some of the view. Mostly it was built of giant stone brickwork, done in various shades of gray, now splattered with old gore and demon blood.

As they searched for survivors and scavenged for supplies, Cortez spoke up. "So, Ward…"

"Yeah?" Jack asked, glancing at the man. He suddenly sounded subdued, almost anxious, which was strange given how relentlessly jovial he'd been so far.

"This other place, the other dimension..Hell. You've been there."

"I have."

"Even if all this goes off without a hitch, we drop the bomb and it closes the portal, I'm assuming we're going to have to go there. Either for research or maybe to assassinate some important demon or hit them on their home turf, whatever the reason. They're gonna need a lot of good Marines for it, and I'm guessing I'll be going. So...what's it like? I mean what's it really like? Do you think I can handle it?" he asked.

"Oh. Yeah, you can handle it," Jack replied.

"You sound really confident. I mean, I never really believed, you know? Not for real. I tried, but-"

"It isn't really Hell though. Look, I know these things are scary, and we're calling them demons, but they aren't really. Or, if they are, it's not like...real, if that makes sense? Like they aren't magic or something. It's not like they're coming after us just because we all did bad things. They weren't tormenting people's souls over there. It's just a crazy alternate reality and they just kinda match up with our own mythology, okay?"

"You sound really confident," Cortez repeated.

"I was there," Jack replied. "It was awful, don't get me wrong. I'd rather be back fighting in fucking Peru. Shit, I'd rather be back in fucking Estonia man, and I'm sure you heard how bad that got. But it's not, like, actual Hell. You don't go there when you die if you're bad."

"What if we do, you just didn't see that part of it?"

Jack sighed. "I don't know...at the end of the day, all I can tell you is what I saw when I was there. The sky is red and black, there's all sorts of crazy shit...it's cold. There's weird buildings everywhere. Sometimes they look like old castles, sometimes they look like UAC buildings, but old, ruins, which should be impossible. Sometimes they look like...I don't even know. There's black sand. There's lava and acid. Black rock mountains. Deadwood forests. Weird-ass coral stuff and rocks that have blue and red glowing veins of I don't even know what. But it's not, like, biblical Hell. I just don't believe it. It's just something I know in my bones...I don't know why. Maybe I'm wrong, but I really believe it's some other dimension and we're just calling it Hell, and we're calling these things demons, but really they're closer to aliens."

He looked down at one of the dead Imps, then sighed and kicked it in disgust. "They're mean and ugly and absolutely brutal, but we can kill them. Pretty sure you can't clear a room full of actual biblical demons with bullets and plasma. And if you can? Then what do we got to worry about? We kick ass with the best of them."

Cortez laughed and seemed to relax. "Yeah...you're right." He sighed and looked up at a corpse chained to one of the walls, one leg ripped off, claw marks all over the body. Some poor bastard who'd gotten caught up in the chaos. "Still really fucking sucks, though."

"Yeah. Still really sucks," Jack muttered. "Let's see what's upstairs."

They'd come to a stairwell cut into the stone wall and cautiously moved up it. As they reached the top and cleared the immediate area, Jack paused and tried his radio. "How's it going over there, Abrash?"

"Fine, Ward," Abrash replied. "Just killing monsters, nothing else to report. You?"

"Same, although we've got a creepy dark hole in the wall that we've got to walk into now."

"Shit. Good luck."

"Yep. Hopefully there's a keycard in there. Talk to you in a bit." He switched back to his assault rifle and flicked on the full-auto, and then activated the flashlights on his suit. He glanced at Cortez. "You ready for this?"

"Yeah, I'm ready," he replied.

"I got point, watch my six."

"Understood."

The light revealed that the hole in the wall led to a tunnel that was uncomfortably narrow and was made of some sort of bumpy gray rock that set him on edge. Something about it made his instincts ping out a warning.

Don't go in there.

Gotta go in there, Jack thought unhappily, and led the way. Sometimes, maybe often, that was your job as a Marine: go into the bad places fighting your instincts the whole way. Because something important was probably in there. And so Jack moved in, walking slowly down the tunnel that was too narrow and just barely tall enough to admit him. He kept forcing himself to put one armored boot in front of the other, listening closely for any little signs that might tip him off and save his life. There was nothing, it was dead silent in there save for them.

But something was waiting for them ahead. Jack was certain.

The tunnel curved a little and then abruptly came to a left turn. Up ahead, there was light. It was red, flickering, and eerie.

Jack suppressed the urge to curse and pressed on. He was infinitely grateful for Cortez at his back. They came out of the narrow confines of the tunnel into a small cavern where the roof was still too low for comfort. It was roughly octagonal in shape and the strange red light seemed to be coming from everywhere and nowhere.

And at its center…

"What the fu-is that what I think it is?" Cortez whispered.

"Yep," Jack replied. "Human heart."

"What the hell is it doing here? Why is it still beating?" he muttered.

The lump of red muscle that sat pulsating on a rusted copper pedestal in the center of the room was a thing of marvelous revulsion. Jack cautiously approached it, checking a few other tunnels that led out of the room for immediate threats and, upon finding none, coming to stand cautiously and reluctantly before the heart.

"No idea," he said. "All I know is that I've seen them before, and I don't suffer them to live. We've got no idea what kind of technology or magic or what the hell ever they have access to. I don't want to chance that this is somehow, someway keeping someone alive and in torment somewhere. Or if it's somehow powering this area. We still have no idea how they transform the world. Be ready, they sometimes react poorly to this."

Jack pulled out his combat knife as Cortez tensed, and he plunged it into the heart. There was an awful spray of blood, but it stopped beating. Ripping his blade out, he wiped it off as best he could and replaced the knife, then looked around. "All right, come on."

They spent several long, unpleasant minutes checking out the side access tunnels. Two of them dead-ended abruptly, and one had a pile of naked corpses. The final way forward let into a similar tunnel, but this one was flooded with a few inches of that strange blue liquid that wasn't water. They kept going, both sternly silent as they walked on and on, navigating the strange rock labyrinth. Jack began having trouble keep tracking of where the sound was coming from as the pair of them splashed down the passageway.

Something about the rock was freaking him out. It seemed somehow ancient, which should be impossible given how recently it had appeared. But where had it come from? Was it manifested from nothing, or maybe swapped from the other dimension? How the hell did it even work? He was still thinking about that when he turned a corner and saw something yellow.

"Keycard," he said. "I'm going for it. Be ready."

"Check," Cortez replied.

Jack switched back to the double-barrel, checking for anything out of the ordinary. Nothing but rock and shadows that swelled and swayed under his flashlights. The tunnel seemed straightforward enough, just twenty feet of rock-walled passageway between him and the card. With a sigh, he set off. One foot in front of the other. Listening, watching, waiting. Hoping. Nothing along the walls, nothing along the ceiling, nothing wrong with the floor.

Beyond the vague anxiety the weird rock was giving him.

But that was common enough for anything that had to do with the other place.

Ten feet went by. Fifteen. The tension swelled as he came to stand before the yellow keycard that sat on the ground in the dead-ended passageway. Jack glanced back down the length of the tunnel, seeing only Cortez, waiting for him. He crouched down, snatched it up, pocketed it, and stood while turning back around and getting his double-barrel in hand as quickly as he could. And not a second too soon, either. Right as he got his finger back on the trigger, there was a flash of light directly in front of him. Jack reacted without thinking as he saw a tall, skeletal figure pop into existence barely a foot away. He aimed and fired.

He gave the damned Revenant both barrels.

Its head vaporized before it had a chance to so much as shriek, and the big bony bastard dropped into a heap at Jack's feet.

"Dammit!" he snapped, cracking open the weapon and reloading rapidly. "I knew it! I knew it! Never easy with these fuckers!"

"You okay?!" Cortez called.

"Fine!" Jack finished up and started walking back. He activated his radio. "Found the keycard. Anything on your end?"

"Just a lot of demons, fed them all their daily recommended dosage of lead," Abrash replied dryly. "We've reached a dead-end and are heading back to the main acid room."

"Same. Meet you there. Out."

He reached Cortez and they began navigating their way back through the dark rock labyrinth. Jack kept expecting something else to pop into existence, or to leap out of some shadow that was deeper than it appeared, but they navigated their way back to the central room with the acid pool without running into so much as a single Imp or zombie.

They sprinted across the acid pool to the final platform opposite the one they'd initially entered through and peered through the bars, seeing another dimly lit tunnel awaiting them.

Jack sighed heavily as he readied the keycard. He was long past getting sick of this. "Everyone ready? Ammo topped off?" he asked.

They all responded affirmatively.

He slotted the keycard and watched the bars slide down into the floor, granting them access to the tunnel.

Gun in hand, he led the way yet again.