Vonnie tracked their progress with a heads-up display as they scrambled through gaps and pockets, jumping a crack and two loose hills of debris.
The ghost sought every possible way up, but they kept losing as much elevation as they’d gained, ducking and weaving for open space. They were forced left, then down, then down again through a pit laced with dry crunchy webs of mineral deposits. It felt like they were running in circles.
“Go back! Lam, go back to that last branch.”
—Radar suggests another upward trend ahead of us.
“Aren’t you headed where we came from?”
—We’ve paralleled several caverns, yes.
“Christ.”
She’d taken the explosive charges with her, so it would be easy to blow the channel behind her and shut off any pursuit, but what if she encountered another foe? What if this tunnel was another dead-end?
Between radar sims and actual footsteps covered, Vonnie’s maps went twenty-two kilometers, although most of that was tangled into a pyramid just eight klicks on a side. Some sections of her trail had also gone unrecorded or were literally nonexistent now. Colossal shafts of ice had been pulverized when the sink hole collapsed. It was unlikely she could retrace her steps even if she wanted to.
“What can you tell me about the new lifeforms?”
—They used many of the same frequencies as the sunfish. I estimate there were only six of them, but the sunfish retreated within seconds of hearing the other sonar.
Vonnie examined a wide vein of rock as they approached. It looked like an excellent place to drop the roof. All she wanted was out. No more data, no more diplomacy, no more trying to vindicate her friends’ deaths. No more guilt.
“If they’re ahead of us, we need to be prepared.”
—I’ve continued to see traces of prints and spoor. Look there. And there.
Across her display, the ghost highlighted four smears of feces on a level spot on the tunnel floor. None was more than a few frozen blotches. In the frozen sky, nothing went to waste or was left behind.
That made her feel awful again. Compared to Europa, her planet was unspeakably rich. She wasn’t sure if it was even possible for her to comprehend how their poverty affected them.
Did the sunfish routinely scout the impermanent, snarled labyrinths in the ice? That could account for why they appeared to know these dead zones so well even when there was no food, no breathable air, and only a few drips of liquid water for them to use for oxygen. She’d seen no food sources other than the bugs, bacterial mats, and a few blots of fungi.
Was that why they were chasing her? To eat her?
She recalled the admiration she’d felt when she first connected the sunfish with the carvings at the top of the frozen sky. She’d supposed they explored the highest reaches of their world in the spirit of adventure, like people climbed Mt. Everest… like she’d volunteered for this mission… but she’d ignored the reality of Lam’s models.
On Earth, a balanced ecology had reestablished itself after extinction events like the eruption of the Toba supervolcano or the Chicxulub meteor strike. On Europa, vast swaths of the biosphere had vanished completely, either burned to nothing or devoured by the ice.
Their environment was a patchwork mess of isolated survivors. What if the sunfish were so desperate for calories, they had no choice except to sweep through the ice looking for anything to sustain them?
Pity. Empathy. Vonnie was glad to feel emotions other than revulsion. It kindled something new in her.
For an instant, she was optimistic.
“Why would they gather their feces instead of leaving it as markers?” she asked. “To hide themselves from predators? For fertilizer?”
—That implies they’ve developed agriculture.
“Farms, yes. Why not?” She practically smiled. Haggling with the ghost reminded her of talking to the real Lam. “They could grow fungus for food.”
—It may be more likely that they use dung for insulation or cement. It would be difficult to seal rock structures with ice.
“Cement,” she said, brooding out loud.
The sunfish might have camouflaged a hundred passageways around her, covering traps and doorways with matching rock. The ghost would sense any that weren’t airtight, but how many clues had she missed?
“Tell me what you can about the dung and give me a detailed read if we find any more.”
—I believe the feces belonged to the new lifeforms. We’d need to stop for a thorough analysis to confirm, but it contained unique, indigestible nubs of cartilage from the sunfishes’ arms. It also looked to contain high concentrations of sodium chloride.
“You mean salt.”
—Yes. The sunfish carry it in poisonous levels in their skin.
“So whatever pooped here, it eats sunfish.”
—In retrospect, there’s a high probability the sunfish pursued us beyond their territory and we’re now in the home of the new lifeforms. Alternatively, these catacombs may be no-man’s-land where both sides conduct raids on each other.
Vonnie shook her head. Even with her weapons and size, she hadn’t been able to make the sunfish run away. Whatever these other creatures were… if they scared the bloodthirsty sunfish…
Maybe she’d been luckier than she thought.
18.
Her suit scampered into a hole like a storm pipe. Then her right knee gave out. Vonnie smashed into the rock and bounced away. In the air, she tensed, fighting to keep her face from hitting next.
Her suit hurt her neck when it contorted like a cat. Lam patted her left heel and one hand against the wall, correcting her spin before he regained speed and clawed up through the maze with her bad leg trailing awkwardly, protecting it.
“Lam?” she said. “Thank you.”
—Are you injured?
“No. Uh, no. Don’t interface with the med systems. My leg’s okay. Tell me about the suit.”
—Every anterior cable in the knee snapped and one medial.
They were falling apart. Her armor had never been intended to take this kind of abuse. Vonnie wasn’t doing much better. She was punch-drunk on stress and stimulants. It had been sixty-one hours since she’d slept. She didn’t want to make the wrong decision.
“How long for repairs?”
—Without the proper tools, our best option might be to scavenge material from the ankle, weld it solid, and restore some function to the knee. I estimate that would take an hour.
“No. Keep going.”
If they stopped, she was afraid she’d close her eyes. She should rest, but closing her eyes would feel too much like being blind again.
According to his sims, they were approximately two kilometers down. Soon they needed to transition from rock to ice. This mountain rose up like a fin, always narrowing, disappearing before it neared the surface — but there would be islands suspended in the ice, free-standing hunks as large as Berlin and gravel fields like sheets and clouds. The trick was to find a gas vent that went all the way up. The trick was to ascend without touching off a rock swell.
Vonnie avoided the thought. Too much planning would overwhelm her.
They ducked a bulge in the ceiling and the gap opened into an ancient volcanic bubble. Half of it was glutted with ice, but just to look across three hundred meters of open space was disorienting. Vonnie felt the same uncertainty in Lam. The ghost scanned up and back.
“What do you think?” she said. “There’s definitely some new melt over there. If we dig, we might get into a vent. We could leave this mountain and close the hole behind us.”