Rue cursed. It made an awful kind of sense. The worst part was, trapped as they were, there was nothing she could do about it.

Well, that might be true. But she'd be damned if she would let herself be bullied anymore.

"We need to plan our response," she said. "How are we going to head Crisler off, assuming we get out of here?"

Mike and Barendts glanced at one another; she saw a faint smile hover around the marine's lips for an instant. Then they leaned forward and started scheming.

TWO MORE DAYS passed before they got the opportunity they were looking for. By that time the air in the submarine was growing stale, the recyclers pushed to their limits. There were signs that the ship's power was fading. Herat said it had a typical muon-catalyzed fusion reactor, little more than a tank of hot hydrogen gas surrounded by muon-generators. Not much could go wrong with the generator itself; power must be bleeding off into the water around them. The oxygen recycling system also worked well; its pedigree was hundreds of years of closed system spaceship design.

More immediate was the fact that they were out of food. The sub continued to drift under the vast ice-sheets of Oculus. Rue watched that strange ceiling pass overhead for hours at a time, feeling frustrated and angry beyond any means of description. She felt now like anger was all she would ever feel. Mike's presence was comforting, but until all of this was over, she couldn't let herself give over to grief. She held his hand and drew on his silent strength, but that was as much as she would allow for now.

In turn, he seemed to be keeping her at a distance. He seemed guarded, as though she had offended him somehow. Once she saw him holding his offline datapack, contemplating it as though debating what to do with it. When he saw her looking, he quickly put it down with a hurried smile.

Strangely, it was Herat whose conversation helped pass the time best during the long hours of waiting. It was now clear that a whole ecology flourished down here and he was studying it as best he could in the illumination of their dimming floodlights. At its base were kilometers-long filaments, rich in metals, that drew electricity from the global currents that the magnetic field of Colossus sent through Oculus's oceans. The filaments used electricity the way plants elsewhere used light, so they formed a robust basis for the flourishing of thousands of species of plant and animal. Herat could sit rapt for hours, staring at the clouds of krill and the icicle-like holdfasts that hung from the glacial ceiling.

Naturally, then, it was he who first saw the lights in the deep.

"I knew there'd be something," he said, after calling them all to the front of the vessel. Where he pointed, Rue could see a deep, diffuse blue, radiating up from the depths. They had switched off the external floodlights to conserve power, so the light could not be reflecting back from some submerged mountain.

"Why is it below us and not above?" asked Barendts. Herat shrugged.

"Mining, maybe? The only way to get many minerals and metals on this planet is to dredge the bottom."

The lights slowly resolved, like waking ghosts, into spotlights that illuminated giant gantries. Taut cables hung from the gantries, disappearing into the gloom below. The gantries were mounted into the glacial ceiling, but they could see no sign of control stations or submarine docks there. What exactly these cables did remained a mystery.

"Should we try it?" asked Barendts, gesturing to the laser rifle still held in the sub's metal arms.

Rue pictured them bickering while their only chance drifted away behind them. "Let's do it."

Barendts sat down in the copilot's chair, rubbing his hands. "Action at last," he muttered, setting his hands on the controls for the manipulator arms. He had been practicing over the past days, learning how the limbs amplified his own movements. Once he'd gained confidence, he and Herat had gingerly transferred the laser rifle from the large arm it was hanging off to a small set more suited to fine work. Then they'd fired a test shot with the laser, just to make sure it would work.

Herat's plan was brutally simple. The front part of the sub was an egg made of transparent diamond-matrix. Behind that was more ordinary machinery, made of metallic hydrogen impervious to almost any pressure. The lasers of Barendts's former friends had wreaked havoc amid this machinery. It was dead weight now: ballast. Herat proposed to cut it away.

Rue kept watching the gantries slide by while they maneuvered the arms around to aim the rifle at the back of the sub. Suddenly she saw a glimmer of bright light ahead and above— a line on the ice ceiling that rapidly grew into an oval of glowing green. "Look!"

It might have been a natural formation— a weaker and softer core of ice that had melted upward, forming a natural dome in the ceiling kilometers across. One or two nukes could have carved it out in seconds. As the highest point for many kilometers around, such a dome would naturally pool any gases that bubbled up from the ocean depths. Humans could as easily have pumped nitrogen and oxygen into it, until now there was a round cathedral of ice, hundreds of meters of airspace above the ocean, lit with floodlamps and with many buildings bolted to the ice around its periphery. Rue stared, fascinated, at spindle-shapes bobbing in the water that must be the hulls of boats or subs like the one they were in now.

The whole cavern was only a few kilometers across. "Hurry, or we'll miss it!" Rue said. Barendts was frowning, obviously trying to decide what structural members of the sub to cut first.

"Fuck it," he said. A line of bright blue light suddenly joined the laser to the back of the sub. Bubbles shot up in a row from a centimeter or so above this line and bright flares of light splashed out from the back. Barendts waggled his hands and the bright line zipped back and forth, impossibly fast.

The sub lurched. Rue watched a large piece of machinery plummet into darkness. "Good," she said. "I think we're rising."

"Just to be sure," said Barendts and waved the beam again. Bright sparks flew and abruptly the cabin lights went out and the noise of fans that had been omnipresent for days, ceased.

"Oops," said the marine. "I guess we're committed now." Rue could barely see his shrug in the blue glow from the approaching cavern.

They were rising, but not fast enough. Rue watched in frustration as bright water began to scroll past overhead. She saw catwalks, boats tied up just meters above them.

"Maybe we should swim for it," she suggested hesitatingly. Herat shook his head.

"We'd freeze to death or drown— or both," he pointed out. "Listen, Barendts, does that laser have a flashlight setting? Maybe we can get someone's attention."

"Good thought." The marine pointed the laser upward and fired it. The bright blue light jutted up, throwing wild shadows across the wavering image of the cavern's ceiling.

"No flashlight setting, by the way," said Barendts, just before a huge chunk of ice slammed into the water meters away. "But that ought to get their attention."

They were barely a meter below the surface now, but the current had taken them almost all the way across the cavern. She saw the ice ceiling coming up again ahead of them.

Suddenly light flooded the cabin. Underwater spotlights had come on around the periphery of the cavern. Now the sleek shapes of divers appeared in the water, wrapped in bubbles like spiraling wings. Six or seven of them swam after the sub.

"Here we go," said Barendts. The lines of blue light shot out from the vicinity of the divers and sparks flew right below where Rue was standing. She jumped in surprise.

The sub's manipulator arms, including the laser rifle, sank quickly out of sight. One of the divers approached them, his own rifle held out prominently.