It was dead.

The Engineer snaked a tentacle around the weapon and tugged it away from John's grasp. It cracked the case and peeled the housing open. The tip of one of its tentacles split into a hun- dred needle-fine cilia and swept over the inner workings. A mo- ment later it reassembled the weapon and handed it, grip first, to the Master Chief.

The needier hummed with energy, and the glassine quills the weapon fired glowed a cool purple.

"Thanks," he whispered.

The Engineer chirped.

The Master Chief edged around the brace. He waited, needier held tightly in his hand, and became completely still. He had all the time in the world, he told himself. No need to rush. Let the enemy come to you. All the time— A Grunt poked its nose over a crate, trying to spot its enemy; it took a blind shot down the corridor and missed.

The Master Chief remained where he was, raised the needier, and fired. A flurry of crystal shards propelled down the passage and impaled the Grunt. It toppled backward, and the shards detonated.

The Master Chief waited and listened. There was nothing ex- cept the gentle thrumming of the reactor.

He moved down the corridor, weapon held before him as he cleared the room. He was careful to watch for the faint rippling of air that would alert him to the presence of camouflaged Elites.

Nothing.

The Engineer floated behind him, and then accelerated toward the disengaged power coupling. It hissed and chittered as it rapidly manipulated a small square block of optical crystal, un- scrambling the internal circuit pathways.

"Cortana," he said. "I've gotten to the coupling. The Engineer appears to know what it's doing. You should have power for the Slipspace generator in a moment."

"It's too late," Cortana told him.

CHAPTER NINE

1827 hours, September 22,2552 (Military Calendar) \ Aboard unidentified Covenant flagship, uncharted system, Halo debris field.

The flagship plunged through Threshold's churning atmo- sphere. Cortana could not hold the ship's attitude. It wobbled and blasted a fiery scar through the clouds, slowly rolling to port on its central axis.

Without shields, the flagship's hull continued to heat to seven- teen hundred degrees Celsius. The nose glowed a dark red, which spread into an amber smear along the midsection and be- came a white-hot plume at the ship's tail. Conduits and feathery antenna arrays melted, separated, and left a trail of molten metal in an explosive wake. Shocks rippled along the frame as the overpressure shed off the bow in waves. The friction from the planet's dense atmosphere would shred the ship in a matter of seconds.

"Cortana," the Master Chief said. "I've gotten to the coupling.

The Engineer appears to know what it's doing. You should have power for the Slipspace generator in a moment."

"It's too late," Cortana told him. "We are now too low to escape Threshold's gravitational pull. Even at full power we can't break our degrading orbit. And we can't tunnel into Slip-space, either."

The incoming Covenant fire had forced them deeper into the atmosphere. She had pushed their trajectory to the edge of what had been safe—it was that, or be engulfed in plasma. But she had saved them from one death ... only to delay that fate by a scant minute.

She recomputed the numbers, thrust and velocity and gravita- tional attractions. Even if she overloaded the reactors to critical-meltdown levels, they were still stuck in an ever-descending spiral. The numbers didn't lie.

The Master Chief's Engineer must have repaired the power coupling, because the Slipspace generator was functional again— for all the good it did them.

To enter Slipspace a ship had to be well away from strong gravitational fields. Gravity distorted the superfine pattern of quantum filaments through which Cortana had to compute a path. Covenant Slipspace technology was demonstrably superior, but she doubted that the enemy had ever attempted a Slipspace entry this close to a planet.

Cortana toyed with the idea of trying anyway—pulse the Slip-space generators and maybe she'd get a lucky quadrillion-to-one shot and locate the correct vector through the tangle of gravity-warped filaments. She rejected the possibility; at their current velocity, any attempt to maneuver the ship would send it into a chaotic tumble from which they'd never recover.

"Try something," the Chief said to her with amazing calm.

"Try anything."

Cortana sighed. "Roger, Chief."

She booted the Covenant Slipspace generators; the software streamed through her consciousness.

The UNSC Shaw-Fujikawa Slipspace generators ripped a hole in normal space by brute force. But the Covenant tech- nology used a different approach. Sensors came online, and Cor- tana could actually "see" the interlacing webs of quantum filaments surround the flagship.

"Amazing," she whispered.

The Covenant could pick a path through the subatomic di- mensions; a gentle push from their generators enlarged the fields just enough to allow their ships to pass seamlessly into the alter- nate space with minimal energy. Their resolution of the reality of space-time was infinitely more powerful than human tech- nology. It was as if she had been blind before, had never seen the universe around her. It was beautiful.

This explained how the Covenant could make jumps with such accuracy. They could literally plot a course with an error no larger than an atom's diameter.

"Status, Cortana?" the Master Chief asked.

"Stand by," she said, annoyed at the distraction.

At this resolution Cortana could discern every ripple in space caused by Threshold's gravity, the other planets in this solar sys- tem, the sun, and even the warping of space caused by the mass of this ship. Could she compensate for those distortions?

Pressure sensors detected hull breaches on seventeen outer decks. Cortana ignored them. She shut down all peripheral sys- tems and concentrated on the task at hand. It was their only way out of this mess: They'd get out by going through.

She concentrated on interpolating the fluctuating space. She generated mathematical algorithms to anticipate and smooth the gravitational distortions.

Energy surged from the reactors into the Slipspace generator matrices. A path parted directly before them—a pinhole that be- came a gyrating wormhole, fluxing and spinning.

Threshold's atmosphere throbbed and jumped through the hole—sucked into the vacuum of the alternate dimension.

Cortana dedicated all her runtime to monitoring the space around the ship, and risked making microscopic course correc- tions to maneuver them into the fluctuating path. Sparks danced along the length of the hull as the nose of the flagship departed normal space.

She eased the rest of the ship through, surrounded by whirling storms and jagged spears of lightning.

She pinged her sensors: The hull temperature dropped rapidly and she registered a series of explosive decompressions on the breached decks.

Cortana emerged from her cocoon of concentration and im- mediately sensed the electronic presence of the other near her, monitoring her Slipspace calculations. It was practically on top ofher.

"Heresy!" it hissed and then withdrew... and vanished.

Cortana pulsed a systems check along every circuit in the ship, hoping to track the Covenant AI. No luck.

"Sneaky little bastard," she broadcast throughout the system.

"Come back here."

Had it seen what she had done? Had it understood what she'd just accomplished? And if so, why declare it a "heresy"?

True, manipulating eighty-eight stochastic variables in eleven-dimensional space-time was not child's play... but it was possible that the other AI would be able to follow her calculations.

Perhaps not. The Covenant were imitative, not innovative; at least, that's what all the ONI intelligence gathered on the col- lection of alien races had reported. She had thought this was exaggeration, propaganda to bolster human morale.

Now she wasn't so certain. Because if the Covenant had truly understood the extent of their own magnificent technology, they could have not only jumped into Slipspaceyrow a planet's atmosphere—but jumped into a planet's atmosphere, too.

They could have simply bypassed Reach's orbital defenses.

The Covenant AI had called this heresy? Ludicrous.

Maybe the humans could eventually outthink the Covenant, given enough access to the enemy's technologies. Cortana real- ized the humans actually had a chance to win this war. All they needed was time.

"Cortana? Status please," the Master Chief said.

"Stand by," Cortana reported.

The Chief felt decompressive explosions reverberate through the deck, thunder that suddenly silenced itself as the atmosphere vented.

He waited for an explosion to tear through the engine room, or for plasma to envelop him. He scanned the engine room for any signs of Grunts or Elites, and then exhaled, and stared into the face of death for the countless time.

He had always been a hairsbreadth from death. John wasn't a fatalist, merely a realist. He didn't welcome the end; he knew, though, that he had done his best, fought and won so many times for his team, the Navy, and the human race . . . it made moments like this tolerable. They were, ironically, the most peaceful times in his life.

"Cortana, status please," he asked again.

There was a pause over the COM, then Cortana spoke.

"We're safe. In Slipspace. Heading unknown." She sighed, and her voice sounded tinged with weariness. "We're long gone from Halo, Threshold, and that Covenant fleet. If this tin can holds together a bit longer, I want to put some distance between us and them."

The Chief replied, "Good work, Cortana. Very good." He moved toward the elevator. "Now we have a hard decision to make."

He paused and turned back toward the Covenant Engineer.

The creature moved away from the repaired power coupling and drifted to a scarred, half-melted panel that had been hit with stray plasma fire. It huffed, removed the cover, and delved into the tangle of optical cables.

The Chief left it alone. It wasn't a threat to him or his team. In fact, it and the others like it might be key to repairing this ship, and their continued survival.

He continued to the elevator shaft, stepping over the bodies of the Grunts in the hallway. He nudged them with his foot to make certain they were dead, and then retrieved two plasma pistols and one of the needle launchers.

He entered the elevator shaft, pushed off the deck, and floated upward in the null gravity. The Chief kept his eyes and ears sharp for any hint of a threat as he moved through the corridors to the bridge. Everything was quiet and still.

At the open bridge door, he paused and watched as Warrant Officer Polaski supervised a Covenant Engineer while it re- moved the blasted door control panels. The Engineer turned a melted piece of polarizing crystal before its six eyes, and then picked up an unblemished crystalline panel off the floor and in- serted it into the wall.

Polaski wiped her hands on her greasy coveralls and waved him in.

Thin, blue smoke still filled the bridge, but the Chief noted that most of the display panels were once again active. Nearby, Sergeant Johnson tended Haverson's wounds and Locklear stood guard. The young Marine's eyes never left the Engineer, and his finger hovered close to, though not quite on, his MA5B's trigger.

The Engineer floated back, spun on its long axis, and looked first at Polaski, then the Chief.

A burst of static issued from the bridge speakers, and the Covenant Engineer looked to them and then to Polaski. It tapped the control, and the massive bridge doors slid shut.

The Engineer passed a tentacle over the controls. They flashed blue, then dimmed.

"It locks now," Polaski told them. "Ugly here knows his stuff."

Three ultrasonic whistles filled the air. The Covenant Engi- neer who had just repaired the bridge door snapped to attention, and its eyes peered intently forward. It chirped a response and then floated toward the Master Chief, trying to maneuver behind him.

"What's it doing?" the Master Chief asked, turning to face the creature.

The Engineer huffed in annoyance and tried again to move around him.

The Master Chief didn't let it. While John had seen no hostil- ity from the creatures, they were still part of the Covenant. Hav- ing one at his back grated against every instinct.

"I've told it to repair your armor's shields," Cortana said.

"Let it."

The Master Chief allowed the small alien to pass. He felt the access panel removed from the shield generator housing on his back. Normally it took a team of three technicians to remove the safety catches and get to the radioactive power source. The Chief shifted uneasily. He didn't like this one bit, but Cortana had al- ways known what she was doing.

Locklear watched this and ran a hand over his shaved head.

He stood on the raised center platform and turned to the other Covenant Engineer as it repaired the burned-out displays on the port side of the room. He held his MA5B loosely, but it was still aimed in the alien's general direction. "I don't care what Cortana says," he told the Chief, "I don't trust them."

The Engineer near Locklear floated to the bridge's holographic controls and passed a tentacle over a series of raised dots.

The screens snapped on and showed three Covenant cruisers closing fast.

Adrenaline spiked through the Master Chief's blood. "Cor- tana, quick—take evasive action."

"Relax, Chief," Locklear said. He waved his hand over a holographic control; the images on screen froze. "It's just a replay."

He turned and examined the suspended plasma bolts just as they impacted on the flagship's shields. "Man," he whispered. "I wish our boats had weapons like those."

"We might soon have exactly that, Marine," Lieutenant Haver-son said. He winced and stood, then moved to a screen that showed the storms in the upper atmosphere of Threshold. "Play this one, Corporal."

Locklear tapped one of the controls.

A line of sparkling blue lights appeared on screen, and the nose of the flagship edged into view. The blue line ripped a hole in space, and the ship jumped forward. The clouds of Threshold vanished; there was only blackness on the screen.

Haverson slicked back the strands of his red hair that had fallen into his face. "Cortana," he asked, "has anyone, human or Covenant, ever performed a Slipspace jump from within an atmosphere?"