I nod.

“Cassidy?”

“I nodded! We’re not supposed to talk, remember?”

Chris either chokes or laughs, tightening his grip on my hand. He starts walking forward, and I realize that I have to bend down a little bit to keep from hitting my head on what is now a cement ceiling. We’re in a tunnel, sloughing through sticky grossness that’s been washed right off the city streets.

“I thought these tunnels were supposed to be empty,” I say, disgusted by the feel of dirty water around my ankles.

“They’re abandoned,” Chris whispers, “not empty. Relax. Walking through sewage is better than being arrested.”

Sewage?

I try not to gag. Chris is hunched down more than I am on account of him being six foot four. After a few hours — okay, minutes — of feeling our way down the cold tunnel, I start to feel claustrophobic. Why?

One: There is no light. Two: I feel like I’m trapped in a box. And three: It smells like a bunch of rats came and died down here.

“How much farther?” I ask.

“About a mile.”

“A mile!?”

“Shhh.” Chris slaps his hand over my mouth. “Quiet, remember?”

I move his hand away from my face, noting just how stale and pungent the air is down here. I had expected a cold, freezing tunnel system. Instead it’s almost warm, like no air ever enters the tunnels.

Every once in a while we hear weird dripping or scurrying noises, sending horrible images of Indiana Jonesand the Temple of Doom through my head. I curl my hands into fists and keep my lips pressed together, trying to avoid inhaling any unseen insects.

If Chris is perturbed about being stuck in a hole in the ground, I don’t sense it. His whole body is totally relaxed, his breathing nice and even.

“This is suffocating…” I begin, trailing off as the sound of an engine cuts through the tunnels. It begins as a soft sound, escalating into a full roar. I clap my hands over my ears. The entire tunnel feels like it’s shaking. Above us, a faint square of light is painted across the cement walls of the gutter. The tunnel opens up into a wide space under the sidewalk. Another entrance.

“We must be close to the city center,” Chris says into my ear. “That’s another gutter opening.”

“What’s that noise?”

“Trucks.”

He feels for my hand again. For a few seconds, I can see his face outlined in the shadows cast by the light of the streets above. I breathe in the current of cold air flowing through the opening, freezing in terror at the sound of an AT trooper’s voice:

“Take that one to the camp. I’ll take care of things here.”

A door slams. Another engine starts, shadows flit across the light pouring in from the street. Chris tenses up slightly and tugs on my hands. “Move.”

I get to my feet. We hunker back down and slip into the continuation of the tunnel. The light disappears again, and this time the water is up to my calves. It’s also getting colder, the farther we progress, a weird change from the stale temperatures we ran into before.

I take the opportunity to think about everything Walter told us in the apartment about Omega and wonder why nobody has ever heard of them before. How could we be invaded by an army that has no country, no king, and most importantly — how could nobody even know that these people existed? Why do the troops speak different languages? Are they all paid hit men, and if so, where did Omega find enough people to create an army big enough to invade an entire country? How long have they been planning this?

These are the totally normal thoughts that run through my head as we sneak around in the dark tunnels beneath the city.

Every once in a while we come to another gutter opening, tiptoe past the lights and voices, and slip into the next tunnel. It’s impossible to get lost because there is only one tunnel. We just keep following it until our necks ache from hunching over for so long and I’m pretty sure the smell of rotting leaves is permanently stamped into my brain.

“Smell that?” Chris suddenly says.

“What?”

“Fresh air.”

I sniff, catching a whiff of cold, clean air. It’s blowing through the tunnel pretty quickly, too. “We must be at the basin,” I say.

“Yeah. That was faster than I thought.”

Sure. Only two solid hours of tromping through the sewers.Piece of cake.

We pick up the pace, following the clean scent of open air. Chris stops unexpectedly and we bump into a solid wall. I experience a flash of panic. Is it a dead end? Have we been sealed in here for all eternity? Am I destined to become a Mummy?

The claustrophobia is doing weird things to my mind.

“What…?” Chris murmurs, sliding his palm across the cement. “Ah.”

“What is it?”

“The tunnel’s curving.” He walks forward and sure enough, we both follow the wall into a neat left hand turn.

I clap my hands together, natural light spilling into the tunnel. Even though it’s nighttime, it seems extraordinarily bright compared to the total blackness of being underground. “Freedom!” I exclaim.

I jog forward, getting down and crawling on my hands and knees towards the exit. Chris crawls behind me, the two of us tired of twisting our necks for two hours. Flecks of rain blow on my face from outside. I come to the edge of the tunnel, cautious about sticking my head out into the open without making sure it’s safe. I’ve seen too many television shows to be that naïve.

So I inch forward, peeking outside. The first thing I see is a wide-open expanse of darkness. It must be the empty basin. The second thing I see is the sky. The third thing I see is Chris crouching in the mouth of the tunnel, a frown on his face.

Because then my other senses kick in and I hear it: Water lapping against the side of the basin. I squint at the basin again, my eyes adjusting to the light.

The basin is full of water.

“What?!” I exclaim, shocked. “He said this thing was empty! Where did all this water come from?”

“Not from this tunnel, obviously.” Chris is rubbing his chin. “It’s about twenty feet from here to the top of the basin. It’s a slope. You can climb that.”

“How deep do you think that water is?” I ask, sticking my hand out. I dip my finger into the water. It’s freezing cold, leaving traces of silt on my fingertips.

“Doesn’t matter,” Chris shrugs. “The only thing that matters is that we’re out of the city, and we did it without getting arrested.”

I take a deep breath and brush some stray strands of hair out of my face. I stand up and wrap my hands around the top of the tunnel, leaning over the water and looking up. Chris is right. The top of the basin is only about twenty feet away, and it’s sloped enough that we could climb it.

“Go ahead,” I say, shivering.

“Ladies always go first,” Chris replies, standing up beside me. “I’ll be right behind you.”

I scowl, swinging my feet out of the tunnel and into the hard surface of the basin. The sound of the water lapping against the dirt is seriously freaking me out, because if there’s one thing I hate even more than small, dark spaces, it’s dark, deep water.

I dig my hands into the dirt and lie on my stomach against the ground. The angle’s not too bad. I climb up on my hands and knees, hearing a soft pat as Chris swings onto the ground below me.

“Race you to the top,” I say.

“Get ready to lose, kid.”

I pick up the speed, trying to go fast enough to beat him, but slow enough to avoid skidding downhill. I start laughing, actually enjoying myself for the first time since…well, since the apocalypse.

“Eat my dust,” I tease, turning my head up towards the top of the basin. I inhale sharply, a tall man short hair staring straight at me.