The data took Vorrin eight minutes this time.

  He ran it twice, which Jessica had learned was its own kind of signal... twice meant he'd found the answer on the first pass and was running it again because he didn't want it to be right. Then he ran it again.

  He lowered the scanner.

  "The explosion didn’t happen historically; it changed things. The damage compromised the primary support structure in the upper passage," he said. "The progressive failure we were modeling over four days..." He paused. "The timeline has collapsed. Twenty hours. Maybe less."

  The cave went quiet in the way it did when the humans stopped moving, and the only sound was water and the soft bioluminescent conversation of the Umara going about their morning.

  "Twenty hours," Khamm said through the comm.

  "Yes."

  "Then we take them now." Her voice had shifted into the register she used when she was solving rather than feeling. "We move the window up, we ..."

  "Khamm," Vorrin said quietly.

  "We have the cube array, we can adjust the parameters..."

  "Khamm." He pulled up the secondary scan overlay and turned it so Jessica could see, then angled it toward the comm pickup so Khamm could read it from the ship. "The surface fauna."

  Silence.

  Jessica looked at the overlay. She'd seen it before ... the rust-colored terrain, the dense sideways-growing vegetation, the root network spreading through the soil. She looked at it differently now. At the density of the roots and what was directly below the densest concentrations, and the two-thousand-year relationship between what was above and what was below, that nobody had known about until a geological survey moved something they'd deemed worth moving rather than destroying.

  A civilization that knew this plant mattered without knowing why. It became intrinsic to their culture, their identity.

  "The dependency," Khamm said. Flat. She'd already seen where it was going.

  "The Umara's biological material returning to the soil over two millennia. The mineral composition is specifically complementary to what the surface fauna requires. It's not incidental nutrition ... the entire developmental trajectory of the surface plant life is built on what the Umara left behind." He lowered the scanner. "If we take a breeding population, we remove the source from this location permanently. The surface fauna doesn't collapse immediately, but the projected divergence over generations is ..." He stopped. "I can't clear the verification parameter. I've run it multiple times."

  The cave breathed around them.

  "So we can't take them," Maddie said.

  "No."

  She didn't say anything else. Just looked at the Umara moving through their morning patterns, the bioluminescence shifting between them in the slow language of a species that had been having this same conversation, in this same cave, for longer than anyone in this cave had been alive.

  Thessarn had not moved from the wall. Jessica looked at him. He was watching Vorrin with an expression she couldn't fully read... not satisfaction, she was almost certain of that. Something more complicated. The look of someone who knew the difference between being right and being glad about it.

  *  *  *

  It was Khamm who found the next problem.

  She'd been running calculations, communicating with the ship, trying to find any angle the verification parameter might flex on, any interpretation of the dependency data that left a door open. Jessica could hear it in the quality of her silence through the comm... the specific texture of someone working very hard at something they already knew wasn't going to work.

  Then a different silence. Shorter. The silence of someone finding something they weren't looking for.

  "Vorrin," she said. "The water."

  He was already reaching for the scanner.

  The contamination had been moving through the water table since the explosion. The mineral deposit the blast had compromised was leaching slowly, the concentration building in the underground spring that fed the cave pool. On the far side of the cave-in... where Khamm could still read the environmental sensors through the ship's systems... the water was within safe parameters. Barely, and falling, but within them.

  On their side, it was not.

  "How long have they been drinking it?" Jessica said.

  Vorrin looked at the readings. At the Umara, moving through the space around the water source. At the pool itself, still clear, still running in its thin ribbon from the wall, carrying what it was carrying that no one could see without a scanner.

  "Since the explosion," he said. "Approximately fourteen hours."

  Vorrin stepped closer to the water source and lowered the scanner toward the thin ribbon spilling from the rock. The display shifted from clean greens into creeping bands of amber and red.

  "It’s not fast," he said. "Not dramatic. The compound binds slowly at first. It accumulates in tissue before it presents. They won’t feel it immediately. There will be fatigue. Coordination drift. Then systemic failure as it reaches the neural lattice."

  The Umara nearest the pool paused, its bioluminescence brightening briefly as another approached. A ripple of light passed between them ... steady, conversational.

  Jessica swallowed.

  "They don’t even know they’re sick," Maddie said.

  "No," Vorrin said. "Not in any framework we can model."

  He lifted the scanner. For a moment, his hand remained hovering over the water as if proximity alone might change the result.

  "It looks clean," Maddie said.

  "It always does," Deke replied quietly.

  "And the effects ..."

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  "Progressive. Given their biology and the concentration curve..." He paused. "A week. Maybe slightly more for the strongest individual. After that..."

  He didn't finish.

  Jessica looked at the Umara. One of the creatures was moving in its slow patterns between the two cohort members. The cohort members near the pilings were going about the ritual of placement with their characteristic deliberateness. These creatures, who had been poisoned by an explosion they'd had no part in causing and didn't know about and couldn't be told.

  "The one on the other side of the cave-in," she said.

  "Unaffected. The contamination hasn't reached that section of the water table." He pulled up the projection. "Simple chance kept it away from the water source, leaving it safe… for now. Considering the nature of the compound in the water, it could be thought of as a mercy that they won’t be around to suffer through it."

  One.

  The word sat in the cave like the rock that had come down in the upper passage ... solid, immovable, taking up exactly the space it took up.

  "We save it," Khamm said it before anyone else could. Not aggressively. Just clearly, the way she stated things, she'd already decided. "Whatever time it has, it has it on the ship in a habitat instead of in a poisoned cave. That's not a difficult ..."

  "It is, though," Deke said.

  Everyone looked at him. He was leaning against the cave wall with his arms crossed, looking at the Umara near the pilings, and his voice had the flat quality it got when he was saying something he'd thought through rather than something he was reacting with.

  "We've had this conversation," he said. "Sort of. We had it about the Snarric." He looked at Khamm through the comm pickup. "The male. Alone in that habitat." He paused. "You've seen him. Both of you have. The way he moves. The way he ..." He stopped. Started again. "He's alive. He's healthy by every measure. Vorrin can run. And he is not okay." He looked at the connector, moving its slow rounds between the cohort members. "These things talk in light. They have a word ... or whatever their version of a word is ... for the one who carries communication between groups. That's not instinct. That's culture." He looked at the Umara. "You put one of them in a habitat alone, and you haven't saved it. You've just changed how it ends."

  The cave was quiet.

  "Deke ..." Maddie started.

  "I'm not saying it doesn't matter," he said. Not harshly. "I'm saying we have to be honest about what we're actually doing."

  Thessarn pushed off the wall from where he had been watching. Before he could say anything, Vorrin spun around to him.

  “Don’t… you… dare… You don’t get a say in this.” His voice was tight as he advanced on the avian. “You left… You abandoned the mission… You abandoned Khamm. I don’t know how you ended up here with us. There’s no way you could have predicted the timing of this mission happening, and yet, you still show up with that condescending look on your face.”

  Khamm was quiet for several long moments. Jessica heard her breathing through, steady and controlled, which meant she was holding something carefully. The conflict plain on her face

  "So we leave it," Khamm said finally. "We leave it here with the poisoned water, and we watch, and then we go."

  "I don't know," Deke said. "I just know what alone looks like. I see it every time I go to the habitat."

  “No,” Maddie said, voice barely above a whisper. “I can’t accept that there is nothing we can do. Why else are we here if we do nothing?” She left, moving away from the group deeper into the cave.

  *  *  *

  Jessica found Maddie later near the water.

  She was sitting close enough to the pool that the bioluminescence of the nearest Umara reached her, casting slow patterns across her suit. The connector had drifted to within a few feet of her... not interacting, just present. Its chest markings moved in their slow, steady pulse. She could see the splint still on its leg from where they had attempted to heal it.

  Maddie was watching it with an expression that had stopped trying to be anything other than what it was.

  Jessica sat beside her.

  "We have to leave it," Maddie said. Not a question. She'd already been here a while.

  "I think so," Jessica said. "But I want to ask you something first."

  Maddie looked at her.

  "When you woke up on the ship," Jessica said carefully. First day. What if it had just been you?"

  Maddie's expression shifted.

  "No me," Jessica said. "No, Deke. Not even Trent with his uncomfortable attitude. Just you, alone, surrounded by people who weren't human and a situation you didn't choose, and nobody who knew what a Georgia thunderstorm smelled like or what it felt like to work a double because your boss decided his time was worth more than yours." She kept her voice gentle. "How long do you think you would have been okay?"

  The cave pulsed its slow light beside them, reflecting the light from the Umara as they moved about.

  "I wouldn't have been," Maddie said quietly. "Okay. At all." She looked at the Umara. At the connector, moving between the two cohort members with ease through long practice. "I would have been alive, and I would have been..." She stopped. "It would have been really bad."

  "Yes," Jessica said.

  "And we can't take the others because of the flora dependency, and even if we could..."

  "Even if we could," Jessica said. "Separating them."

  Maddie was quiet for a long moment.

  The pacing creature paused in its movement. Looked at them... or did whatever the Umara equivalent of looking was, those luminous eyes settling on the two humans sitting by its water source. A single line of light traveled from its chest to the tips of both hands, brief and clear.

  Neither of them moved.

  Then it turned and went back to its rounds.

  "It has hours and doesn’t even know," Maddie said. "Maybe a little more."

  "Yes."

  "With its group." She said it slowly. Like she was building something out of the words as she said them. "In its cave. Doing..." She gestured at the pilings, the art on the eastern wall, the slow bioluminescent conversation filling the space. "This. All of this. Until it can't."

  "Yes."

  Maddie looked at the water. At the pool that looked clean and ran clear and was doing what it was doing invisibly, the way so many things did their damage.

  "That's better," she said. "Isn't it. That's actually better than the alternative."

  It wasn't a question exactly. It was someone arriving at something the hard way and needing to say it out loud to make sure it was real.

  "I think so," Jessica said. "I think it has to be."

  Maddie nodded once. Looked at her tablet. For a long moment, she didn't open it.

  Then she did. Started writing.

  "Okay," she said. Quiet and certain and sad in the specific way of someone who has understood something they would rather not have had to. "Okay. We leave it, but we do what we can not to forget it."

  *  *  *

  They spent the remaining hours the way Vorrin spent problems he couldn't solve... by documenting everything he could instead.

  The bioluminescent lexicon. The cave art scans. The social structure mapping, the pilings, the ritual of placement, and the connector's patterns cross-referenced against observable responses from the group. Actions and behaviors had no context to understand, but maybe someone might. They built the rough skeleton of a record for a species that would have no living speakers in less than a day, and they did it with the focused precision of a group who had decided that bearing witness was the only form of help still available.

  They recorded the cadence of light pulses and mapped them against spatial movement. They catalogued the specific angle at which stones were placed at the pilings and the subtle adjustment pattern that followed… always once, never twice. They scanned the mineral content of the art pigments pressed into the eastern wall and archived the exact wavelengths of their bioluminescent speech.

  They were no longer modeling survival.

  They were preserving existence.

  Vorrin adjusted the cube array to capture volumetric recordings of the cave interior, down to particulate distribution in the air. Khamm synchronized the ship’s core storage to triple redundancy. Maddie tagged each file not with numbers but with descriptors: Morning Pattern. Water Exchange. Connector Path. Cohort Placement Ritual.

  No one suggested efficiency.

  No one suggested stopping.

  They worked with the quiet intensity of a wake.

  Deke helped without being asked.

  He sat beside Vorrin with a secondary scanner. He called out pattern observations in the flat, practical voice he used when he was doing something difficult and not making it about himself. The injured Umara moved close to them as the hours passed. Not interacting. Just present, in the particular way it had been present near Deke since the rock. Its chest markings moved in

  that slow, steady pulse.

  Deke didn't look at it directly. But he didn't move away.

  Maddie wrote.

  Thessarn stood near the cave art for a long time. Not helping, not interfering, just present with the quality of attention that Jessica had come to recognize as his version of witness. He looked at the shapes pressed into the rock... the water source, the antler structures, the rows of repeated marks... with the focused stillness of someone memorizing.

  Jessica watched him and thought about what he'd said in the dark of their hours trapped together. About the direction you weren't watching.

  She thought about Rask.

  She thought about the explosion that had caused all of this.

  She wasn't done with that conversation. But it could wait until they were outside, in the rust-colored light, with the cave behind them.

  Some things need open air.