We've been walking for what feels like an hour, although I'm sure it can't possibly be that long. It just seems longer with the pain flaring through my ankle with every step.

Elias has gone out a couple of yards ahead of the rest of us, leaving me with America and Star.

"What if we are going in circles?" America asks. "We can't get any signal down here." He taps the side of his helmet where the radio connects in for the tenth time in the past five minutes, like if he hits it enough it will miraculously start working. "We have no way of knowing which way we are even going."

"We can't be going in circles," Star says. "We would have to reach a junction for that to be possible. Other than where that worm crossed the path, the tunnel's been one shot the entire way."

I lick my dry lips. Thirst scratches at the inside of my throat. "We're going to need water eventually," I say. "We aren't going to be able to keep walking like this indefinitely." My mind flashes to when we first woke up on the starship and discovered Carl's body. He was just a skeleton in that pod—long dead by the time we found him. His bones were dried like ancient fossils.

How did he die? Did he suffocate? Die of thirst?

If we don't find a way out of these tunnels, are we going to die the same way? I try to push the thoughts from my mind, but they creep back to me, latching on like tiny parasites.

"Hey guys," Elias calls out, startling me from my thoughts.

"What?" I ask.

"Look." He points up ahead.

For a second, I'm not sure what I'm looking at. Our headlamps illuminate a rough, dark surface in the distance.

"Shit," America hisses under his breath.

"Please tell me that's not a dead end," Star says.

America jogs ahead of the two of us. When he catches up to Elias, he stops. Then, he turns back to face us, a smile on his face. "It's not a dead end," he says.

"What is it then?" Star asks as the two of us reach the guys.

Elias gestures toward the left. "Our tunnel splits down there."

I bite my lower lip, angling my head lamp so it shines down the path, illuminating the rough surface of the cave. After a hard turn to the left, two tunnels merge in a wye with ours.

"Which way do we go?" I ask.

"So . . ." Star trails off. "I guess we don't know where either of them go. Let's just pick one."

A chill creeps across my skin. The feeling of claustrophobia and agoraphobia mix together in a nauseating cocktail. When there was only one path, there was no wrong way. But now, one of these paths might be only a mile from the surface, while the other might lead us on a spiral into the depths of this maze. If we pick wrong, we could be walking for ages without even knowing how close we might have been had we picked the other path.

Based on the uneasy faces on my crew mates, I suspect they might be having similar thoughts.

"What if we split up?" America offers after no one says anything for a while.

"Absolutely not." Elias smacks him lightly on the back of the helmet. "No splitting up."

"Fine, okay," America says. "You're right. No splitting up. But then how do we pick?"

"Anyone have a coin?" Elias asks.

"Has anyone even seen a coin in the past fifty years?" America says under his breath.

"Wait," Star cuts in.

"What?" I ask.

"Everyone just be quiet for a second." She brings her hand in front of her face, raising one finger as though to shush us. "Do you hear that?"

We all go quiet. My eyes dart around the pockets of darkness, as though looking at it might somehow help me hear what we are listening for.

"There," she whispers.

I hold my breath, straining my ears to listen.

Thump. Thump. Thump.

My heart skips a beat when I hear it. The sound echoes up to us from the path leading down to the right. It's rhythmic, like a pulse. My mind rushes back to the months I spent in that Godforsaken prison beneath the Earth. In every room of that dungeon, water leaked from above. It pounded against the floor. The walls. Like the beating of a heart—a constant reminder of the world carrying on above while all of us down under were as good as dead.

"Water," I whisper. "Something's dripping down there." I point in the direction that the sound is coming from.

"Exactly." Star nods. "And if there is water dripping, that means it has to be dripping from somewhere. The surface, maybe."

"That's the way we go," I say. "That's our best bet."

As the four of us set out, I shine my light down the other tunnel one last time. The fear that maybe we are making the wrong choice is something I can't shake. For some reason, I'm reminded of an old poem I read in the fourth grade so many years ago, but for the life of me I can't remember what it was called. I think the scenery described in it was more beautiful than my view from here, though. I'd rather be in a yellow wood than a tunnel of red.

The other path fades into the distance, and my thoughts of poetry also drift away. The uneven ground of the tunnel slopes downward like shallow stairs in an ancient temple as we descend deeper beneath the surface. I brace myself against the side of the cave to keep as much weight as possible off my ankle. The coolness of the mold-slicked surface seeps through my gloves, and my leg pounds with each step I place on it.

The ticking of dripping water intensifies. I chew on the insides of my cheeks. My mouth is so dry, and the idea of drinking it when we finally reach the source dances through my mind, but I dismiss it immediately for being stupid. We'll drink water when we get back to the starship. I'm not going to risk drinking anything I find on this planet without making absolutely certain first that it has been purified.

"Are we sure this is the way we should be going?" America slows his pace, allowing me to catch up as the others continue on ahead. "It's only leading us deeper underground."

"Maybe not," Elias calls back, "but there's no way to be sure unless we see this route through to the end. Or, at least until we get to wherever the dripping is coming from."

"Maybe we should try the other route instead," America suggests. "This one just seems like a waste of time."

"You got a hot date to get to or something?" Star shoots back.

"No," America mutters under his breath. He kicks a small pebble down the tunnel. It ricochets off the floor and the side of the cave before striking Star in the back of her calf.

She turns and glares. "Stop kicking shit at me, Canada."

"Accident, sorry." He raises both hands in the surrender position.

Star finally nods and turns her gaze away, back to the path ahead.

America shakes his head and looks off to the side. "It wasn't supposed to go this way," he says lowly to himself.

"What way was it supposed to go, America?" I ask.

"Huh?" he turns to me.

"You keep saying this isn't how this was supposed to go. Well, what were you expecting to happen on this mission? What did you think it would be like when we got here?"

"Oh." He pauses, avoiding eye contact. "I don't know, I guess. But it wasn't getting picked off one by one by the local infestation and being trapped underground, that's for sure."

I nod slowly. "Yeah. I didn't leave one prison just to get sent to a worse one."

"This isn't prison, Shawn," he says. "This is Hell." A pause. "No wonder they never announced this shit to the public. Sending humans here was a mistake."

I grimace as the pain in my ankle intensifies, and I pause to lean against one of the rocky walls, resting my leg. America stops and waits with me.

"America, how did you find out about it, then?" It's the question that's been burning at the back of my mind, I just haven't had the chance to ask yet. I have my theories, but I want to hear him admit them. I want to hear that I'm right. "You knew about the mission before you faked that crime, didn't you? You had to have."

He looks away from me. "I did."

"How?" I ask. "How did you find out about it?"

He responds with silence.

"You worked for them, didn't you?" I ask. "What was the deal? Are you some sort of inside guy sent along to babysit the rest of us because we can't be trusted? Is that it?"

"It doesn't really matter anymore, does it, Shawn?" He keeps his voice calm, but his jaw tightens, and the muscles in his neck strain.

"So, I'm right?"

"Yes, okay, but it doesn't fucking matter!" he snaps.

"It does, though." I keep my tone steady even though he's raised his voice at me. "Because you know more than the rest of us. What aren't you telling us? Is colonization even the real reason for this mission? What else do you know?"

"Nothing, okay?" He clenches his hands into fists. "Look, I don't know any more about the mission than what they told all of you. I wasn't lying when I told you I was an engineer, just about the sort of engineering I was doing. I was hired at the Interstellar Colonization Corporation right out of college, and ICC put me on the team working on the design of our starship."

"I don't believe you're a rocket scientist," I say.

"Of course you don't." He shakes his head. "But believe it or not, I was. That is, until I learned what the mission of the starship we were working on was actually going to be. I thought ICC would only be designing unmanned craft for exploration for the next thirty years, at least. When I learned they were actually planning to send humans to Ace on the ship . . ."

He trails off and looks off to the side, his headlamp illuminating the rust-red mold at the base of the tunnel.

"What?" I finally ask.

"I told you before," he says. "It'd always been my dream to go into space. I thought designing the starships that went there would be the closest I'd ever get. It was never my plan when I first started working at ICC to actually go on the mission, but as soon as the idea came to me, I couldn't let it go. I convinced the mission director of my plan, and he agreed. I'd fake a crime, and once I was in prison, they'd select me for the first mission. Having someone on the team from the inside to make sure things didn't get out of hand . . . it made sense."

I nod. It does make sense. When Duke Green first told me about this mission, I thought it sounded ridiculous to entrust a bunch of criminals with such an expensive asset. Sending someone along from the inside makes sense.

"Wait." I furrow my brow as something America said jumps out at me. "You said first mission?"

"Yeah," he replies. "First mission."

My stomach rolls over in my gut. "You mean there are going to be more?" The idea of other starships filled with humans destine to land—destine to die—on this alien planet chills me to the bone.

"We started construction on three starships while I was working there," America says. "Scarborough, and her sister ships, Charlotte and Alexander. There were plans to build three additional ones, too—a six-ship fleet."

I open my mouth to respond, still not sure what I'm going to say, but before I can get a word out, I'm interrupted.

"Hey Shawn, America!" Star's voice echoes back to us from down the tunnel.

I turn my headlamp in the direction it comes from, but the beam only illuminates the curve of the tunnel ahead—rock and stone mottled with deep-red mold. How far ahead have Elias and Star gotten?

"What?" America shouts back.

"Get over here," Star yells.

"You're going to want to see this," Elias adds.