It's useless, We’re already through.

  The Doctor follows in after me, her footsteps too loud on the wet concrete, her breathing too fast. Behind us the klaxon wails, growing fainter with each step, falling off as we run through the corridor.

  I hate this. Too many variables I can't control. But I'd considered the possibility of a hard exit, traded three cans of fuel and a favor to some data-hoarder with an architectural obsession for the maps to make it work.

  Inward. I lead us deeper, our forms wrapped in flickering red light that sputters like a dying pulse.

  "You've been down here before." The doctor's voice comes from behind me. Not a question. I turn anyway. She holds out a surgical mask, another already pressed to her own face. Her eyes track my shoulders, my spine. Reading something I'd rather she didn't see. "You know the rumors. What lurks in this place."

  "I've been down here. Generally." Good, keep it neutral. Don't give too much away. "It's all the same, really.”

  The emergency strips gutter out one by one as we press forward. First the ceiling fixtures. Then the wall-mounted backups. Eventually total darkness forces us to stop, I have us wait and blink while waiting for the doctor's eyes to adjust. Mine at least, system enhanced as they generally didn’t have this problem anymore.

  We move forward ahead and eventually to the left. A faint gray-green luminescence bleeds from a ragged gap in the corridor wall. Bioluminescent moss, System-spawned. It colonizes anywhere with moisture and organic runoff.

  Which means sewers. Which means our exit.

  I move closer. The moss clings in thick clumps around a section of wall that doesn't match the rest. Sheet metal. Riveted in place over a hole roughly five feet in diameter. The welds are sloppy. Maintenance crew work, not engineering. Done fast, by people who wanted to be somewhere else.

  A patch job meant to seal something out.

  Or in.

  The concrete around the metal's edges is off. Not cut, not drilled, more torn. Something pushed through from the other side, tunneling through rebar like wet straw. The patch came after.

  "The rumors," Rios says. Her voice is barely above a whisper. "The sounds in the pipes. Maintenance teams that never come back. That's not… that's not merely a rumor?"

  "No." I don't elaborate but I can tell she wants me to, perhaps even expects me to.

  I test the sheet metal with my palm, it really was sloppy. Whoever did this work didn't expect it to last. Didn't expect to need it too.

  I search, finding a supply closet to my left. I pull it open, scan the inventory. Crowbar, rusted but functional. Industrial scrub brush with a steel handle. Improvised weapons aren't ideal, still useful for what comes next.

  I jam the crowbar's flat end behind the sheet metal and wrench. The first rivet pops like a gunshot in the silence. Rios flinches. I'm already on the second.

  Three more rivets. The patch crashes inward, clanging against something wet on the other side. The moss light spills into the gap, illuminating a passage that descends into black.

  The smell hits next. Stagnant water, rust, decay and something that reminds me of the time I toured a meatpacking facility for a commodities play. That deal fell through too.

  "Through here." I strap the crowbar to my pack and put the brush handle in my main hand.

  We pass through. The torn edges scrape my shoulders, concrete giving way to the slick curve of old pipe. I focus on the sensation of rough stone and cold moisture. The give of fungal growth beneath my boots. Trying not to focus on the size of what made this tunnel. Not what I’ve let it become.

  More gray moss clings to the walls ahead. Everything was washed-out monochrome. No reds down here anymore, only light that makes you forget color exists.

  "Watch your step." My voice dies two feet from my mouth as the floor shifts underfoot. Old tile fracturing into bare concrete, concrete dissolving into something wet.

  If you stumble upon this tale on Amazon, it's taken without the author's consent. Report it.

  "There's a junction about two hundred meters ahead. We go left, follow the main drainage line. Eventually we find…"

  "What's causing the disappearances?"

  Her voice echoes. Bounces off walls I can barely see. Traveling down tunnels in directions I can't track.

  "Keep. Your voice. Down."

  "Then give me an answer." But she says it softly now at least.

  I stop and turn in the dim light bleeding from the ramp behind us, I can make out her face. Stubborn, defiant, refusing to move forward on faith alone. Good, a sheep might not survive what I will need her to do.

  "Something lives down here," I say. "Something unlike the monsters above." Before she can speak again, I hold up my hand. "I don't have time for your education. Every minute down here is a minute more we risk, that Lily risks.."

  "Who's Lily?"

  "My sister. My little sister.”

  I don't know why I added that. Why did I feel the need to clarify it?

  We’re moving forward again, twenty seconds of silence pass between us against the backdrop of our feet moving. Then her footsteps stop again. The junction should be close. Another fifty meters, maybe. If she'd only keep moving.

  “The maintenance teams," she whispers. Quieter now somehow making it feel louder. Still pushing what didn’t need to be asked.

  "Doctor."

  Then I try her name, the one the guards used. "Rios."

  Her eyebrows crease. "You've seen it. Whatever's down here. I can tell. So why won't you just."

  I close the distance until we're inches apart, until I can see the pulse jumping in her throat.

  "Stop. Talking."

  She doesn't flinch, "Why?"

  Because I can feel it now. That pressure at the edge of perception. The hair on my arms standing up for reasons that have nothing to do with the cold. Something is listening. Something close. Something that knows these tunnels better than I ever will.

  The Doctor's mouth opens then closes.

  The System reminds me. It always reminds me.

  I've seen this notification a hundred times. I didn't understand what it meant when I first got it. Didn't understand what the "evolutions" would cost.

  I understand now.

  The moment lasts until the silence stretches it closed. Somewhere ahead, water drips. A pipe rattles. Water sloshes. Normal sounds. Explainable sounds.

  I breathe out slowly, the doctor exhales too, I don’t know yet if she can sense it. If she senses the same things I do. I almost curse her out loud. Almost curse the System too. Neither would help.

  Tugging on her arm I move us toward the junction again, Rio's breathing is ragged behind me. Controlled panic, she's keeping it together, but barely. My silence isn't helping her fear. But she doesn't understand why I can't explain. Why the evolutions prevent me from disclosing what I know.

  Left at the junction. I remember that much from the city maintenance maps I studied yesterday after borrowing them from a municipal office. The pacing of the junctions, the switchbacks where the old storm drains connect to the newer infrastructure.

  Several minutes of this. Then the tunnel opens into a larger chamber. Overflow reservoir, cylindrical, thirty feet across maybe.

  Emergency rungs are bolted into the far wall, leading up to a service hatch that probably hasn't been opened in years. Four drainage pipes feed into the space at different heights. The water here is deeper, thigh height.

  I stop at the chamber's edge and listen.

  Dripping water pitter-patter around me. Always dripping. The echo makes it impossible to locate.

  But there's something else too. A rhythm that doesn't match water.

  Rios leans close. Her lips almost touch my ear.

  "Which way?"

  I point to the rungs on the far wall. The service hatch above them. An exit that might work, if the lock hasn't rusted shut, if the grate above isn't welded down, if a dozen other variables I can't calculate from here align in our favor.

  "I'll check the hatch. You stay below the ladder."

  Rio's eyes widen, "You're leaving me alone?"

  "I'm climbing twenty feet Rios. You'll be able to see me the entire time."

  "..."

  "There’s no sense in trapping us both on the same ladder. I'll be thirty seconds tops."

  "Well at least call me by my name then, I’m Sofia."

  “Good to meet you Sophia.” She waits for me to return with my own name in kind but I ignore giving out such a thing and cross the chamber. The water drags at my ankles, knees, hips. Then the rungs, cold under my fingers. Slick with condensation and something that might be algae or fungi. Sofia follows and waits at the bottom like I asked.

  I climb until the hatch is above me.

  Once there, I twist it, and it opens easier than I expected. Someone broke the lock months ago, left it hanging loose. I push the duffel through the gap and secure the exit. Then pull the hatch mostly closed again. No sense advertising our escape route.

  I look down. Scan the pipes and the water. The shadows pooling near the eastern drainage line are too thick, too still.

  There.

  Movement, subtle. A shape separating from the darkness of the second pipe. Then another from the third. And another. And another.