We left to explore down the slippery tunnel late that night. It might have made more sense to leave after a good night’s rest, but neither of us could sleep, and spending so much time down there meant night and day were increasingly academic concepts anyway. Niko caffeined up (I was jittery enough already), and we loaded our packs with canned food and power bars, thick gloves, and crampons from the sporting goods store. “12 points of contact ensures solid grip on ice,” the box had said. We didn’t expect the manufacturer had tested them on moldy carpet, but it was the best we could do.

In my pack was also a gun. I bought it from a place I’d driven past every day on my way to work but never gone into until that morning. The friendly clerk agreed to waive the mandatory waiting period in exchange for the last of my ATM cash. I didn’t tell Niko about the gun. I thought it would make me feel safer but it just felt heavy.

It had been a hot day and the old house clung to that heat through the night with grim brick desperation. Descending into chillier air was a relief. With every step down the headaches diminished, our mood improved. It was almost addictive, being down there.

We retraced our route through the upper halls to the top of the shaft, and reset the grapples. This time, Niko hammered them into the doorjamb, face set, until he’d driven the steel spikes three inches into the wood. Even so, neither of us really expected they’d still be there when we got back.

When, or if.

Getting down was a familiar exercise now, danger mitigated by procedure and repetition. We retraced our route to the tiled room with the sink via the shortcut we’d found. The water was still running, hot and steaming, rushing across the floor to the corner with its angled hallway lined with slimy black carpet. We shined our lights down the hot throat and the steam grabbed their brightness, bounced it back to us maliciously. We couldn’t see more than a few body lengths down.

Niko ran a hand through his curls, deflating again in the hot moist air; scratched the hair behind his ear furiously, like a dog with an itch. He was shaking. “Are we sure about this? Really really? Because it sort of seems like a colossally stupid thing to do.”

“You have a better idea?”

“No. Is that what lemmings say to each other, you think? Before jumping?”

“The lemming thing is a myth.” I shrugged out of my pack and unzippered it, digging for gear. “Walt Disney made it up because a bunch of wiggling rats made for boring footage. Good story, though, isn’t it?”

He sighed, looking down the steaming shaft unhappily.

“No, I don’t have a better idea,” he said at last.

We pulled on the crampons and the heavy gloves. Harness, rope, knots. Check. Niko pounded two new Grapple Buddies into either side of the angled tunnel entrance. We tied on. Double-check.

Then, each holding our rope, kicking hard to sink the sharp toes of the crampons deep into the slimy carpet, we started down.

It was slow, hot work. Once we got inside the slanted hall, the steam was oppressive, everywhere: we were instantly drenched with it, like rot-smelling sweat. Even with the crampons our feet constantly slipped. The sludge was deep and slick, a stew of algae and mold and fungal slimes, green-black and stinking of putrefying jungle, of horrible things happening under your carpet, inside your walls. We held tight to the ropes with steam-wet gloves. The floor and walls twisted and bent as we descended, as if the constant moisture had warped them, but the downward angle stayed relentlessly vicious.

It was a gullet. We were letting ourselves be swallowed. No—worse. We were forcing ourselves in. Eager. Like we couldn’t wait to be digested.

We were nearing the end of our first hundred feet of rope when everything went to shit.

All at once we were sliding. Our ropes had gone slack in our hands, no longer connected to anything. There was no time to dig in with our crampons; we were already moving too fast, careening down the hallway like a grotesque slalom. Neither of us screamed, focused I guess on trying to grab hold of something, anything, but there were no doorways, no light fixtures, nothing but the thick hot slime and the scalding water. I tried to dig my feet into the oozing carpet but my loose rope had entangled me, my pack was in my way, my face was smeared with scalding gunk and I couldn’t open my eyes.

My hand closed on Niko’s leg and I grabbed it. A moment later the floor angle shifted and he cried out, threw his body sideways, brought us both to a shuddering, squelchy stop.

We were soaked through, overheating. Scalding water ran down the slope past us. I blinked my eyes open and saw he’d wedged himself into a kink in the tunnel. One of his knees was scraped open and a dull red mark on his forehead was beginning to swell. But he’d done it. He’d stopped us.

Ropes slithered down the tunnel past us, followed moments later by two grapples still tied to their ends. Niko reached out to grab one with his free hand, but his weight shifted, and he had to throw the hand back against a wall to re-brace, cursing. I tried to snag them with my foot, but didn’t even come close. They vanished down the tunnel, trailing rope.

Niko’s face was tight. He tilted his head down toward me. “This was a mistake. God, we’re so fucking stupid. Ryan, man. We have to go back.”

“Calm down,” I gasped, head filled with the roaring of the water, blinking gunk from my eyes. “Don’t panic. We can do this.”

“Man, I’m barely holding on. I don’t know how much longer I can keep from slipping. We have to try to climb back up.”

“Back?” I said, confused. “You want to go back?”

He stared down at me. “Of course back. Are you fucking crazy? Where the fuck else?”

“There’s nothing good up there. Nothing right.” I kicked my foot for purchase, managed to rest at least some weight on a hidden protuberance. “Besides, nothing’s changed. The plan’s still the same. This is the best lead for finding a way back to our side.”

“Are you not paying attention?” he hissed, furious. “Something is trying to kill us.”

“So let’s find out how to stop it.” I tried to keep my tone reasonable. “We’re halfway down already. Climbing back up will be hard, regardless. Why not get all the way to the bottom first?”

“Because we don’t even know if there is a bottom.” His face was blotched red with fury, with sweat, with the scorching heat of the air. “Halfway? We have no fucking idea how deep this goes. I should have said this a long time ago. You’re obsessed. You get obsessed a lot, man, let it drag you down. Your stupid records.” He took a deep breath. “Well now you’re obsessed with this place, and it’s blinding you. It’s feeding on you, your obsessions. Multiplying them. You can’t see it, or maybe you don’t want to, but I do. I’m looking right at it. Like the gorilla in the crowd.”

I was angry. “If I’m obsessed with anything, it’s with finding a way back. We’re running out of time. We either figure this out, or we’re stuck here forever, on the wrong side. We need each other to get through this.” I said it again, like saying it could make it true. “We need each other.”

“You’re obsessed with me, too,” he muttered. “When was the last time you hung out with someone else?”

“When was the last time you did?”

He shook his head angrily, dismissing this.

“Our housemates,” I pushed, “when was the last time you hung out with any of them? Anyone other than me?” He stared back, seething. “Their names. I bet you can’t even remember their names.” I was bluffing. But could I remember them, either? Names, faces. No. There was nothing. None of those people mattered, not to me, not to us. We were the only thing that mattered. Getting back to where we’d been, what we’d had. What I’d wanted.

He shook his head again, violent, like there was something inside it he wanted to dislodge. “You’re living in a fantasy,” he spat, “you always have been. I can’t be what you want me to be, okay? I can’t be what anyone fucking wants me to be. You all have these versions of me in your head, these ideal perfect Nikos, but they’re not real. I can’t live up to them.” He opened his eyes, stared yearningly back up the shaft. “Help me. If you really care about me, help me back up. Don’t be like everyone else. Don’t just fucking use me to get what you want.”

“Going back’s not going to help. There’s no answers up there.” He wasn’t understanding. I reached for something else. “Those headaches aren’t going away. You think you can live with that pain? Forever?”

“Better than being fucking dead!” He seemed to realize I wasn’t changing my mind, turned away to reach for a handhold, but there was nothing there, nothing to grip, and he scrabbled pathetically at the slime.

“Is it?” I shouted, angry, desperate. I had to say something, something that would make him stay, keep him here, and my mouth raced ahead of me. “You won’t make it up there, not with pain like that. We both know you won’t.”

He tensed, glared down at me. “What the fuck is that supposed to mean?”

“You know exactly what it means,” I said, shaking. “Never really helped you. I’ve done nothing but help you. I’ve always been there for you. Every fucking time you fall I pick you back up. You’d be dead if it weren’t for me.”

He shot me with a gaze of such cold fury I cringed. “You’re fucking poison,” he hissed, “you know that? A fucking snake. I wish you’d let me die that night. I wish we’d never met. Let go of me!”

And his hand did close on something, and he pulled himself up, triumphant. His leg was slipping out of my hands, and I couldn’t bear for him to crawl away from me, couldn’t handle the thought of going back up to that world, to any world where everything was wrong and nothing I wanted was possible, so I pulled. I pulled, too hard, and both his hands slipped, and he crashed back into me, only I wasn’t holding onto anything but him any more so both of us tumbled down, faster and faster, slipping and twisting and scraping together down the steepening blood-hot slope, down and down and down into darkness.