“Yeah, she’s right,” Amos said. He sounded tired. Maybe that was how he expressed sorrow. “That plan’ll kill the captain. It’s off the table.”
“Well. A high-g burn would almost certainly break me into tiny pieces right now. But that doesn’t necessarily take it off the table.”
On the bulkhead, the creature moved. It wasn’t much, but it was there. Prax zoomed in on it as best he could. One massive clawed hand—clawed but still with four fingers and a thumb—braced it, and the other tore at the bulkhead. The first layer was fabric and insulation and it came off in rubbery strips. Once it was gone, the creature attacked the armored steel underneath. Tiny curls of metal floated in the vacuum beside it, catching the light like little stars. Now why was it doing that? If it was trying to do structural damage, there was any number of better ways. Or maybe it was trying to tunnel through the bulkhead, trying to reach something, following some signal …
The cotton ticking disappeared, resolving into the image of a pale, new root springing from a seed. He felt himself smile. Well, that’s interesting.
“What is, Doc?” Amos asked. Prax realized he must have spoken aloud.
“Um,” Prax said, trying to gather the words that would explain what he’d seen. “It’s trying to move up a radiation gradient. I mean … the version of the protomolecule that was loose on Eros fed off radiation energy, and so I guess it makes sense that this one would too—”
“This one?” Alex asked. “What one?”
“This version. I mean, this one’s obviously been engineered to repress most of the changes. It’s hardly changed the host body at all. There have to be novel constraints on it, but it still seems to need a source of radiation.”
“Why, Doc?” Amos asked. He was trying to be patient. “Why do we think it needs radiation?”
“Oh,” Prax said. “Because we shut down the drive, and so the reactor is running at maintenance level, and now it’s trying to dig through to the core.”
There was a pause, and then Alex said something obscene.
“Okay,” Holden said. “There’s no choice. Alex, you need to get that thing out of here before it gets through the bulkhead. We don’t have time to build a new plan.”
“Captain,” Alex said. “Jim—”
“I’ll be in one second after it’s gone,” Amos said. “If you aren’t there, it’s been an honor serving with you, Cap.”
Prax waved his hands, as if the gesture could get their attention. The movement sent him looping slowly through the operations deck.
“Wait. No. That is the new plan,” he said. “It’s moving up a radiation gradient. It’s like a root heading toward water.”
Naomi had turned to look at him as he spun. She seemed to spin, and Prax’s brain reset to feeling that she was below him, spiraling away. He closed his eyes.
“You’re going to have to walk us through this,” Holden said. “Quickly. How can we control it?”
“Change the gradient,” Prax said. “How long would it take to put together a container with some unshielded radioisotopes?”
“Depends, Doc,” Amos said. “How much do we need?”
“Just more than is leaking through from the reactor right now,” Prax said.
“Bait,” Naomi said, catching hold of him and pulling him to a handhold. “You want to make something that looks like better food and lure that thing out the door with it.”
“I just said that. Didn’t I just say that?” Prax asked.
“Not exactly, no,” Naomi said.
On the screen, the creature was slowly building a cloud of metal shavings. Prax wasn’t sure, because the resolution of the image wasn’t actually all that good, but it seemed like its hand might be changing shape as it dug. He wondered how much the constraints placed on the protomolecule’s expression took damage and healing into account. Regenerative processes were a great opportunity for constraining systems to fail. Cancer was just cell replication gone mad. If it was starting to change, it might not stop.
“Regardless,” Prax said, “I think we should probably hurry.”
The plan was simple enough. Amos would reenter the cargo bay and free the captain as soon as the bay doors had shut behind the intruder. Naomi, in ops, would trigger the doors to close the moment the creature had gone after the radioactive bait. Alex would fire the engines as soon as doing so wouldn’t kill the captain. And the bait—a half-kilo cylinder with a thin case of lead foil to keep it from attracting the beast too early—would be walked out through the main airlock and tossed into the vacuum by the only remaining crewman.
Prax floated in the airlock, bait trap in the thick glove of the environment suit. Regrets and uncertainty flooded through his mind.
“Maybe it would be better if Amos did this part,” Prax said. “I’ve never actually done any extravehicular anything before.”
“Sorry, Doc. I’ve got a ninety-kilo captain to haul,” Amos said.