I pull at Lachlan’s arm, distracting him from trying to open the hatch. I point at the shapes, but he doesn’t understand. He thinks I’m gesturing to the hatch, and he holds up one finger: he’ll have it open in a minute. He can’t see what I’m seeing.

He finally gets the hatch open and in the sudden bright overhead light I can see the shapes clearly. They’re fish, moving in a tight school, as gaudily colored as inner circle ladies out for a night on the town. I just see them for a flash, and then they’re gone, and all I see is Lachlan at the round open hatch.

What is happening to me?

The fresh air will clear my head. I can’t wait to tear this rebreather off. I have to suck in every breath as if it is fighting me, and my lungs feel heavy and sore.

But before my head breaches the surface so I can take that yearned-for breath, Lachlan shoves me down again. He pushes up the hatch, kicking hard against the resistance of the water.

He mimes something, and it is a long while before my fuzzy brain figures out that he’s telling me there’s someone up there. We can’t go out yet.

But we have to! There’s something wrong with my rebreather. I’m out of air. Have we been down here an hour? My perception is fuzzy. I don’t know what I’m doing. All I know is that I have to breathe and I can’t with this thing over my face. I start to claw at it, pulling with desperate brute force at first, then trying to get my fingers between the bonded layers. Somewhere in the back of my mind I know this is a terrible idea, but I can’t help myself.

Lachlan tries to stop me, but I fight him as hard as if he’s trying to drown me. That’s what it feels like. Part of me can see his frantic eyes behind his own mask, but anything that keeps this suffocating film over my face has become the enemy.

Finally I tear it off . . . and as the water hits my face I come to my senses. It’s all I can do not to draw in a huge breath. I look through the water, and see a blurry Lachlan inches away. He’s doing something . . . ripping off his own mask. He comes closer. I feel his mouth on mine.

He’s giving me his air. His last breath. Helping me hold on. I feel a moment of relief, instantly clouded by the twin thoughts that there’s no more air after this for me . . . or for Lachlan.

I want to tell him something. Bubbles escape my mouth, and the words are lost to the water.

Then he wrenches the hatch open and shoves me upward. I grab the rim, my head breaches the surface, and I gasp, the first heavenly breath stinging my lungs. I suck in another, and another, before my head clears enough that I remember Lachlan. He went so far back under in his effort to push me to the surface. I start to try to dive under the water to help him—knowing that I’m more likely to drown him than to help him—but without the rebreather I feel like I’m drowning as soon as my face hits the water. I can’t do it!

I kneel at the edge and peer over. He used the last of his air, his strength, to save me. I can see him far below the surface, indistinct. Is he moving? Is he trying? He saved me when I was drowning in the nanosand. “Lachlan!” I call in despair, and plunge my hands helplessly into the water. There’s nothing I can do. He’s just a dim dark shape far beneath the water, sinking deeper every moment.

Suddenly there’s another shape there. In a confusion of movement I see a shadow appear, and merge with him. The shapes get bigger—they’re coming up! There’s someone else down there, pushing Lachlan to the surface!

The second he’s close enough I reach down and grab whatever I can reach, his clothes, his hands, his hair, fumbling for anything to hold on to, and pull him up. His rescuer pushes from below, and scrambles out herself, pulling off her rebreather as she stands dripping.

“Lark!” I gasp. “You were supposed to stay behind, stay safe!”

She gives me a soft smile. “Do you really think I’d let you go into danger alone?” I look down at Lachlan, choking up water at our feet, and want to say that I wasn’t alone. But I let it go. More quietly, Lark adds, “It’s my fault your mother was killed. It’s my fault Ash was captured. I made the mistake of trusting someone. Now I have to win back your trust.”

“Oh, Lark,” I breathe . . . but there isn’t time for more. Lachlan has struggled to his knees. He looks up at Lark, a strange mix of gratitude and hostility in his eyes.

“You’re not supposed to be here,” he says. I can tell he’s deeply embarrassed at having to be rescued. He’s always been the fighter, the strong one.

Lark just shrugs. “Well, I am here. Good thing, too.”

“You can’t come inside with us,” he insists. “You don’t fit into our plan.”

“Luckily, I have my own plan,” she says flippantly. There is a row of lockers against the far wall. She takes out a sealed package, tears it open, and slips on a set of pale green coveralls. She hides her lilac hair under a cap and flashes an ID.

“I’ll pick up some tools and the things I need in another supply closet, and be waiting for you right outside the holding cells. I won’t be able to get any closer than that, but I’ll be ready for anything.”

“You can’t . . .” Lachlan begins, but I cut him off. I know arguing with her is useless at this point. The only thing left to do is make sure she’s in a good position. A safe position.

“You can’t be so close, or you’ll be affected, too. Wait for us near the lobby. We may need your help there.” If all goes according to plan, we can make it out without anyone the wiser. I’m hoping not to involve Lark anymore at all. After Lachlan, Ash, and I get out, she can slip out on her own, shed her disguise, and go home. I need her to be safe. I don’t think I can go through with all the hard things ahead of me if I can’t picture Lark in her bedroom, lying on her mulberry-colored bed, safe and secure.

I latch onto this future, trying not to think about the in-between. After all, we only just made it inside, and we already almost died.

“That’s okay,” Lark says. “I have a couple of tricks up my sleeve. If you get in trouble, I’ll be able to provide a distraction.”

I envision her screaming to draw Greenshirt eyes, or even fighting. “Don’t draw attention to yourself!” I insist.

She pulls the cap down lower. “No one will even notice me,” she says with utter confidence. She looks exactly like an ordinary maintenance worker, so she might be right.