I LANDED ON my feet but, unprepared for the shock, immediately fell backward with a painful thud. Back up, I hopped aside. Not a moment too soon, because Emilio came sailing down the chute behind me, crashing to a stop in the same space I’d occupied a second before.
The flashlight clattered to the ground and broke open, useless. But we didn’t need it anymore. This room was lit with brilliant sunshine.
For a second we were both motionless, staring in awe at the windowed ceiling. Warm and buttery sunshine filtered in from the outside world, from the room where the SLH was parked. It was the most beautiful thing I’d seen in a week.
Then I looked down and realized where we were: on top of one of two tanks, each easily twelve feet tall, so massive they took up half the room.
I spared one last glance upward at the glass ceiling. If only we could reach it—break the glass. Thinking quickly, I took the heavy iron crowbar from my belt loop and threw it with all my strength upward at the glass.
The crowbar bounced harmlessly off the glass, and a metallic clang echoed in the small space as it fell to the floor somewhere below.
I should’ve known. That ceiling could probably stop a meteorite.
“Cass . . .” My attention was diverted. Emilio was still prone, one hand cradling his side, groaning. “I think I broke something.”
He’d landed worse than I thought. I knelt at his side, gave him a once-over. No bleeding, but he groaned louder and sucked in a breath when I tried helping him to his feet.
No time!
“I’ll live,” he said, but his voice was weak. “Go do what you gotta do.”
Hesitating only a nanosecond, I left him, taking the walkie-talkie with me. I found a ladder built into the side of the tank and climbed down into the small room. A few rows of bare metal tables filled the small space. There was a door on the far side, but it was locked.
My foggy brain tried to piece the scene together. The functions of the SLH had been in one of the million manuals they’d given us to study. This was a mock-up, a practice habitat. But in the real one—the one designed for humans to live on Mars—they would grow their own oxygen here. The tanks held water, both potable and to use as a backup source of oxygen. But ours had been modified for use on Earth. No need for plants or electrolysis of water. Instead, a vent drew in air from outside.
“Cass, what’s happening? Where are you?” Luka demanded over the walkie-talkie.
“I’m here,” I said, my voice weak. Talking suddenly required a lot more effort. My lungs were working hard to draw out every molecule of oxygen they could.
“You have to manually open the valve to let in the air. Should be on a wall near the tanks.”
Fighting hard against the dizziness, my unfocused eyes wandered around the room before finding an orange control panel and beneath it, a hand-wheel crank. That had to be it.
“Give me a minute,” I said into the walkie-talkie, and then dropped it with an unspeakably loud clang onto a metal table. Emilio groaned again from the top of the tank.
I grabbed the crank and pulled with both hands. It didn’t budge. Not enough air to fuel my muscles. They were hypoxic, useless.
I breathed quickly in and out through my mouth, purposely trying to hyperventilate, hoping to infuse my blood with as much oxygen as possible. If this didn’t work, then using up my air quicker wouldn’t really matter.
I gritted my teeth and put every ounce of strength into my arms.
The crank groaned, released. Gasping, I spun it open as fast as I could, spots dancing before my eyes.
Nothing was happening. I reached for the walkie-talkie, missed, stumbled and fell to my knees. My vision was going gray. My head felt like a helium balloon, floating above my body.
I reached up to the table with both hands and felt around blindly. Yes! My fingers hit hard plastic, wrapped around it. “Opened,” I gasped into the radio. “Didn’t work.”
There was a moment’s pause. I laid my head against the metal table and listened to my heart struggle to keep going.
The metal was pleasantly warm from the sunlight.
I closed my eyes.
“Pierce said you will need to open the control panel and turn the ventilation system back on. Cassie? Do you hear me?”
His voice sounded different. Distant.
I was so tired. Maybe I could lie down on this table and just rest for a few minutes.
“Cassie? Stay awake, Cassie! You have to turn on the ventilation system! We are almost out of oxygen!”
Oxygen. Right. That’s why I was so sleepy.
But Luka, he was still awake. This exertion might kill me before the others. But I was their only shot.
A picture bubbled up through the fog of my brain. Mitsuko strewn like a discarded doll on the floor. Luka, back in the kitchen, slumped down in his chair, the radio fallen at his feet. Emilio, who’d gone quiet on top of the tank.
Without me, they would die.
I dragged myself to my feet. My heart pounded painfully in my ears as I felt my way back to the control panel.
“I’m here,” I whispered into the radio. “What do I do?”
He recited a code to access the vent system. I punched the numbers dutifully, following his instructions, utilizing every bit of brain activity I had.
For a long time nothing seemed to happen. I collapsed into a heap, my legs unable to support me anymore. Blackness took over my vision, and briefly the world went away.
But not before a mechanical whir reached my ears and I felt a cool breeze rustle my hair.