“Jim,” Naomi said to Holden’s back, but he waved her off and opened a channel to Alex in the cockpit.

“Alex, did we just see what my sensors say we saw?”

“Yeah, Cap,” the pilot replied. “Radar and scopes are both sayin’ Eros jumped two hundred klicks spinward in a little less than a minute.”

“Holy shit,” Amos repeated in exactly the same emotionless tone. The metallic bang of deck hatches opening and closing echoed through the ship, signaling Amos’ approach up the crew ladder.

Holden shook off the flush of irritation he felt at Amos’ leaving his post. He’d deal with that later. He needed to be sure that the Rocinanteand her crew hadn’t just experienced a group hallucination.

“Naomi, give me comms,” he said.

Naomi turned around in her chair to face him, her face ashen.

“How can you be so calm?” she asked.

“Panic won’t help. We need to know what’s going on before we can plan intelligently. Please transfer the comms to me.”

“Holy shit,” Amos said as he climbed into the ops deck. The deck hatch shut with a punctuating bang.

“I don’t remember ordering you to leave your post, sailor,” Holden said.

“Plan intelligently,” Naomi said like they were words in a foreign language that she almost understood. “Plan intelligently.”

Amos threw himself at a chair hard enough that the cushioning gel grabbed him and kept him from bouncing off.

“Eros is really fucking big,” Amos said.

“Plan intelligently,” Naomi repeated, speaking to herself now.

“I mean, reallyfucking big,” Amos said. “Do you know how much energy it took to spin that rock up? I mean, it took yearsto do that shit.”

Holden put his headset on to drown Amos and Naomi out, and called up Alex again.

“Alex, is Eros still changing velocity?”

“No, Cap. Just sitting there like a rock.”

“Okay,” Holden said. “Amos and Naomi are vapor locked. How are you doing?”

“Not taking my hands off the stick while that bastard is anywhere in my space, that’s for damn sure.”

Thank God for military training,Holden thought.

“Good, keep us at a constant distance of five thousand klicks until I say otherwise. Let me know if it moves again, even an inch.”

“Roger that, Cap,” said Alex.

Holden took off his headset and turned to face the rest of the crew. Amos was looking at the ceiling, ticking points off with his fingers, his eyes unfocused.

“-don’t really remember the mass of Eros off the top of my head… ” he was saying to no one in particular.

“About seven thousand trillion kilos,” Naomi replied. “Give or take. And the heat signature’s up about two degrees.”

“ Jesus,” the mechanic said. “I can’t do that math in my head. That much mass coming up two degrees like that?”

“A lot,” Holden said. “So let’s move on-”

“About ten exajoules,” Naomi said. “That’s just off the top of my head, but I’m not off by an order of magnitude or anything.”

Amos whistled.

“Ten exajoules is like, what, a two-gigaton fusion bomb?”

“It’s about a hundred kilos converted directly to energy,” Naomi said. Her voice began to steady. “Which, of course, we couldn’t do. But at least whatever they did wasn’t magic.”

Holden’s mind grabbed on to her words with an almost physical sensation. Naomi was, in fact, about the smartest person he knew. She had just spoken directly to the half-articulated fear he’d been harboring since Eros had jumped sideways: that this was magic, that the protomolecule didn’t have to obey the laws of physics. Because if that was true, humans didn’t stand a chance.

“Explain,” he said.

“Well,” she replied, tapping on her keypad. “Heating Eros up didn’t move it. So I assume that means it was waste heat from whatever it was they actually did.”

“And that means?”

“That entropy still exists. That they can’t convert mass to energy with perfect efficiency. That their machines or processes or whatever they use to move seven thousand trillion tons of rock wastes some energy. About a two-gigaton bomb’s worth of it.”

“Ah.”

“You couldn’t move Eros two hundred kilometers with a two-gigaton bomb,” Amos said with a snort.

“No, you couldn’t,” Naomi replied. “This is just the leftovers. Heat by-product. Their efficiency is still off the charts, but it isn’t perfect. Which means the laws of physics still hold. Which means it isn’t magic.”

“Might as well be,” Amos said.

Naomi looked at Holden.

“So, we-” he started when Alex interrupted over the shipwide comm.

“Cap, Eros is movin’ again.”

“Follow it, get me a course and speed as soon as you can,” Holden said, turning back to his console. “Amos, get back down to engineering. If you leave it again without a direct order, I’ll have the XO beat you to death with a pipe wrench.”

The only reply was the hiss of the deck hatch opening and the bang as it closed behind the descending mechanic.

“Alex,” Holden said, staring at the data stream the Rocinantewas feeding him about Eros. “Tell me something.”

“Sunward is all we know for sure,” Alex replied, his voice still calm and professional. When Holden had been in the military, he’d been officer track right from the start. He’d never been to military pilot school, but he knew that years of training had compartmentalized Alex’s brain into two halves: piloting problems and, secondarily, everything else. Matching Eros and getting a course for it was the former. Extra-solar space aliens trying to destroy humanity wasn’t a piloting issue and could be safely ignored until he left the cockpit. He might have a nervous breakdown afterward, but until then, Alex would keep doing his job.

“Drop back to fifty thousand klicks and maintain a constant distance,” Holden told him.

“Huh,” said Alex. “Maintainin’ a constant distance might be tough, Cap. Eros just disappeared off the radar.”

Holden felt his throat go tight.

“Say again?”

“Eros just disappeared off the radar,” Alex was saying, but Holden was already punching up the sensor suite to check for himself. His telescopes showed the rock still moving on its new course toward the sun. Thermal imaging showed it as slightly warmer than space. The weird feed of voices and madness that had been leaking out of the station was still detectable, if faint. But radar said there was nothing there.

Magic,a small voice at the back of his mind said again.

No, not magic. Humans had stealth ships too. It was just a matter of absorbing the radar’s energy rather than reflecting it. But suddenly, keeping the asteroid in visual range became all the more important. Eros had shown that it could move fast and maneuver wildly, and it was now invisible to radar. It was entirely possible that a mountain-sized rock could disappear completely.

Gravity began to pile up as the Rocichased Eros toward the sun.

“Naomi?”

She looked up at him. The fear was still in her eyes, but she was holding it together. For now.

“Jim?”

“The comm? Could you…?”

The chagrin on her face was the most reassuring thing he’d seen in hours. She shifted control to his station, and he opened a connection request.

“UNN corvette, this is the Rocinante,please respond.”

“Go ahead, Rocinante,” the other ship said after half a minute of static.

“Calling to confirm our sensor data,” Holden said, then transmitted the data regarding Eros’ movement. “You guys seeing the same thing?”

Another delay, this one longer.

“Roger that, Rocinante.”

“I know we were just about to shoot each other and all, but I think we’re a little past that now,” Holden said. “Anyway, we’re chasing the rock. If we lose sight of it, we might never find it again. Want to come with? Might be nice to have some backup if it decides to shoot at us or something.”

Another delay, this one almost two minutes long; then a different voice came on the line. Older, female, and totally lacking the arrogance and anger of the young male voice he’d been dealing with so far.