1802 hours, September 22,2552 (Military Calendar) \ Aboard unidentified Covenant flagship, uncharted system, Halo debris field.

The Master Chief ducked as the hissing energy blade slashed at him. He dived toward the Elite and slammed the butt of his rifle into the alien's midsection.

The Elite doubled over, and the Chief brought the rifle butt down to smash the alien's skull—

But the Elite rolled back. There was a blur of motion as the energy blade lashed out and neatly bisected the assault rifle. The two halves of the wrecked MA5B clattered to the deck.

The blade of crackling white-hot energy narrowly missed the Chief. The MJOLNIR's internal temperature skyrocketed.

He couldn't risk dancing at this range, so the Master Chief did the last thing the creature expected: He stepped closer and grabbed its wrists.

The bands of muscle on the Elite's arms were iron hard, and it struggled to free itself from the Chief's grasp. The Chief wrenched the alien's sword arm and forced the blade away—but this took most of his strength, and he had to weaken his grasp on the Elite's other hand.

The energy blade blurred perilously close to the Chief's head. It missed by a fraction of a centimeter and sent a wash of static across his heads-up display.

The blade was a flattened triangle of white-hot plasma, contained in an electromagnetic envelope that emanated from its hilt. The Chief had seen such weapons slice battle-armored ODSTs in half and gouge gaping wounds in Titanium-A armor plating.

Worse, this Elite was tough, cunning, well trained—and it hadn't spent days fighting nonstop on Halo. The Chief felt every wound, pulled muscle, and strained tendon in his body.

Haverson and Polaski moved onto the bridge, their pistols drawn, but neither of them had a clear line of fire.

"Move, Chief!" Haverson shouted. "Damn it, we've got no shot!"

Easier said than done. If he let go, the Elite would cut him in two. The Master Chief grunted, struggling to turn the Elite. The alien fought back for a moment, then—instead of

resisting—lurched back, right into the path of the Chief's advancing teammates. The Elite flicked the angle of its blade flat so the arc of energy whipped toward Haverson and Polaski.

Haverson screamed and fell to the ground as the energy blade sliced through his pistol and across his chest. Polaski cursed and fired a single shot, but it glanced off the Elite's shield.

The alien glanced at the source of the fire and growled in its guttural, warbling tongue.

"Get the Lieutenant out of here," the Master Chief barked. He raised his knee to his chest and lashed out with a straight kick. His boot connected with the Elite's breastplate. The alien's energy shield flared, then faded, and its breastplate cracked like porcelain beneath the force of the blow.

The alien staggered back, dragging the Master Chief with it. It coughed up purple-black blood that smeared John's visor, obscuring his vision. Its foot struck something on the ground—the alien's fallen helmet—and it lost its footing.

Together they crashed to the ground.

The Master Chief kept his grip on the Elite's sword arm. The alien's other hand, however, wrenched free and grabbed the fallen plasma pistol. The weapon's muzzle charged with sickly green energy.

The Chief rolled to his right as the pistol discharged. A globe of plasma arced across the compartment and splashed over the displays behind him.

The instruments flickered, then flashed and sparked as the energy bolt melted their systems. Before the displays went dark, however, the Master Chief saw one of the Covenant cruisers open fire. A lance of plasma rushed through space toward the flagship.

The Chief and the Elite struggled, rising to their feet. The Chief batted the plasma pistol aside, and it clattered across the control center.

The Elite's mouth opened, and it snapped at the Chief. It was angry or panicking now... and he felt it getting stronger.

His grasp on the alien loosened.

There was motion behind the Elite; Sergeant Johnson and Locklear still struggled to get their hatch open more than a crack. "Sergeant—prepare to fire." "Ready, Master Chief." the Sergeant cried from the other side

of the hatch.

The Chief tightened his grip on the Elite's sword arm, shoved his forearm into the alien's throat and drove it backward, across the bridge. He slammed the creature into the partially opened hatch.

The energy blade cut into the Master Chief's armor, boiling through the alloy that protected his upper arm.

"Sergeant, now! Firer

Gunfire exploded from the hatch, oddly muffled because the rounds impacted directly into the Elite's back. The alien snarled and contorted, but it held on to the Master Chief. The alien warrior sawed the blade deeper, cutting through the tough crystalline layers of the MJOLNIR armor. Hydrostatic gel oozed from the wound... mixed with the Chief's blood.

"Keep. Shooting." A bullet hole appeared through the Elite's broken chestplate— bits of shattered armor and torn flesh spattered over the Chief.

The Master Chief slammed the Elite into the bulkhead, and a control panel behind the alien sparked. The door to the escape corridor hissed open, and the creature reeled back.

The alien was off balance, and the Chief finally had leverage. He bulled the Elite backward and hammered its arm into the wall. The alien metal rang like a gong, and the Elite dropped its energy sword. The blade guttered and went dark as its fail-safes permanently disabled the weapon.

The Chief forced the alien back, step by step. The deck was slippery with blood. Finally he twisted the Elite to the right and launched a powerful open-handed strike into the alien's wounded chest.

The Elite howled in pain and flew back, through the open hatch of an escape pod.

"Get off this ship," the Chief said. He hit a control stud and the hatch slammed shut. There was a sharp, metallic bang as the locking clamps released. The pod screamed away from the hull.

The Chief exhaled. Sweat dripped in his eyes, momentarily blurring his vision. "Good work, Sergeant, Locklear," he panted. His shoulder burned. He tried to move it, but it was stiff and wouldn't respond.

The ship lurched.

"Plasma impact on the starboard foredeck!" Cortana called out. "Shields down to sixty-seven percent." She paused and then added, "Amazing radiative properties. Chief, you need to disable the navigation override so I can maneuver."

Haverson and Polaski strode toward the Chief. Haverson clutched his chest and grimaced in pain from the sword wound. Polaski set her hand on the Master Chief's shoulder. "That's bad," she whispered. "Let me get a first-aid kit from the Pelican, and—"

The Chief shrugged off her touch. "Later." He saw her concerned expression melt into one of... what? Fear? Confusion?

"Cortana, show me what to do," the Chief said and made his way to the raised platform in the center of the bridge. "Polaski, you and Haverson get that other hatch open."

"Aye aye," Polaski muttered, her voice tight. She and Haverson went to the hatch and got to work.

The Master Chief glanced at the control surfaces. As his hand hovered over them, the flat controls rose and became a three-dimensional web of the distinctive Covenant calligraphy. "Where?" he asked.

"Move your hand to the right half a meter," Cortana said. "Up twenty centimeters. That control. No, to the left." She sighed. "That one. Tap it three times."

Faint lights traced the surface as the Chief touched it; they flared red and orange and finally cooled to brilliant blue.

"It worked," Cortana said. "NAV controls coming online. I can finally move this crate. Hang on."

The ship spun to port. On the displays that still functioned, four more Covenant cruisers tracked them—and fired.

The flagship accelerated, but the plasma torpedoes arced and followed them. "No good," Cortana said. "I can't overcome our inertia in this tub. They're going to hit us . . . unless I can get us into Slipspace."

A rhythmic warble pulsed from one of the displays. It flashed red.

"Oh no," Cortana said.

The leading plasma torpedo impacted. Dull red fire smeared across the viewscreens.

"Oh no, what?" Haverson demanded.

"This ship's Slipspace generator is inert," Cortana replied. "The disabled NAV controls were a trick. It must have been the Covenant AI; it lured me here while the drive was physically de-coupled from the reactor. I can maneuver all I want, give orders to the Slipspace generator—but without the system powered up were not going anywhere."

"There's a Covenant AI?" Haverson muttered, and raised an eyebrow. "Upload the coordinates to power coupling," the Master Chief said. "I'll take care of it." Two more plasma torpedoes impacted and splashed across the shield. "Energy shields collapsing," Cortana said. "Brace!"

The last shot collided with the flagship. The hull heated, and plasma boiled layers of armor plating away. The ship rolled as plumes of superheated metal vapor outgassed.

"Another hit like that will breach the hull," Cortana said. "Moving this tub at flank speed." "The power coupling coordinates, Cortana," the Master Chief insisted. A route appeared on his heads-up display. The engineering rooms were twenty decks below the bridge.

"Those won't do you any good," Cortana told him. "There are bound to be Elite hunt-and-kill teams waiting for you. And even if you managed to remove them, there is no way to repair the power coupling in time. We don't have the tools or the expertise."

The Master Chief looked around the bridge. There had to be a way. There was always a way—

He leaned over the edge of the central platform and grabbed one of the Covenant Engineers that cowered below. He dragged it up by its float-sack. The creature squirmed and squealed.

"Maybe we don't have the expertise," he said and shook the Engineer. "But this thing does. Can you communicate with it? Tell it what we need?"

There was a pause. Then Cortana replied, "There is an extensive communications suite in the Covenant lexic—"

"Just tell it I'm taking it to fix something."

"All right, Chief," Cortana said.

A stream of high-pitched chirps emanated from the bridge speakers, and the Engineer's six eyes dilated. It stopped squirming and grabbed hold of the Master Chief with its tentacles.

"It says 'good' and 'hurry,' " Cortana told him.

"Everyone else stay here," the Chief said.

"If you insist," Haverson muttered, his face pale. Blood trickled from the wound in his chest. The Master Chief looked at Johnson and Locklear. "Don't let the Covenant retake the bridge."

"Not a problem, Chief," Sergeant Johnson said. He stopped to kick the dead Elite once in the teeth, then slapped a fresh clip into his MA5B. He yanked the weapon's charge handle, fed a round into the chamber, and stood at arms. "Those Covenant sissies are going to have to tango with me before they set one foot in this room."

On the display two of the Covenant cruisers fired again.

The Chief watched as the plasma raced toward them, fire that spread across the black of space. "Cortana, buy me some time," he said.

"I'll do what I can, Chief," Cortana told him. "But you'd better move fast. I'm running out of options."

Cortana was annoyed. She had let the Covenant AI—for that's what this other presence in the system undoubtedly had to be— trick her. She had gone straight for the simple lockdown of the NAV systems. She never performed a thorough systems check of the ship, assuming that there had only been one point of sabotage. It was a mistake she would never have made if she'd been operating at full capacity.

She checked every system of the flagship. She then locked them out with her own security measures.

Cortana turned off her feelings of anger and guilt and concentrated on keeping the ship in one piece, and the Master Chief alive. No. . . she reconsidered and kept her emotions active. The "intuition" provided by this aspect of her intelligence template was too valuable to deactivate in a battle.

She maneuvered the flagship toward the gas giant, Threshold. The incoming plasma might be disrupted by the planet's magnetic field—if she dared get close enough.

Cortana diverted power from the foreshield to the aft portions, distorting the protective bubble around the flagship. She turned all seven plasma turrets aft and fired a pair of plasma torpedoes at the incoming salvo.

The plasma turrets warmed and belched superheated flame— but it dispersed into a dull red cloud only a few meters from the point of fire, thinned, and then dissolved.

She saw a subsystem linked to the weapons control: an accompanying magnetic field multiplier. That was how the Covenant shaped and guided their charges of plasma. It acted as a sophisticated focusing lens. Something wasn't right, however— something had already been in this directory and had erased the software.

Cortana swore that when she caught this guerrilla Covenant AI, she'd erase it line by line.

Without understanding how the guiding magnetic fields worked, the plasma turrets were no more useful than a fireworks display.

The enemy Covenant plasma charges, however, were tight and burned like miniature suns; they overtook the flagship and splashed over its reinforced aft shields. They boiled against the silver energy until the shields dulled and winked out.

The plasma etched a portion of the aft hull away like hot water dissolving salt. Cortana sensed the dull thumps of atmospheric decompressions.

She checked on the Chief. His signal was still on board, and his biomonitor indicated that he was still alive.

"Chief, are you there yet? I'm down to one last option."

There was a static-filled pause over the COM, and then the Master Chief whispered, "Almost." "Be careful. Your armor is breached. You can no longer function in a compromised atmosphere."

His acknowledgment light winked on.

Cortana pushed the Covenant reactors to overload and plotted a course around Threshold. She had to slip into the outer reaches of its atmosphere. The heat, ionization, and planet's magnetic field might protect them from the plasma.

The flagship rolled and dived into the thin tendrils of clouds. Bands of white ammonia and amber ammonium hydrosulfide clouds snaked in sinuous ribbons. A red-purple spot of phosphorus compounds cycloned and lightning arced, illuminating an intervening layer of pale blue ice crystals.

But their ship no longer had shields. The friction heated the hull to three hundred degrees Celsius as she brushed against the upper reaches of Threshold.

On her aft cameras Cortana saw the trailing Covenant ships open fire. Their shots followed her like a pack of predator birds.

"Come and get me," she muttered.

She adjusted the attack angle of the flagship so it nosed up, which produced a slight amount of lift. She concentrated the building heat toward the ship's tail. A turbulent wake of superheated air corkscrewed behind them.

"Cortana?" Polaski said. "We're approaching the viable edge of an exit orbit. You're getting too close to the planet."

"I am aware of our trajectory, Warrant Officer," she said and snapped off the COM. The last thing she needed was a flying lesson.

The leading edge of the plasma overtook them. It roiled in their wake, churned explosively with the atmosphere. The flagship pitched and dropped in the unstable air, but the plasma diffused and caused them no further damage. Behind the flagship was an unfurling trail hundreds of kilometers long, a wide flaming gash upon Threshold.

Cortana experienced a moment of triumph—then squelched it.

There was a new problem: The concussion from that blast had altered their flight path. The heat and overpressure wave had thinned the atmosphere ... just enough to cause the flagship to drop seven hundred meters. Wisps of ice crystals washed over the prow.

They were too deep now. They didn't have enough power to break orbit. They would spiral into the atmosphere, and would ultimately be crushed by the titanic gravitational forces of Threshold.

The Chief spun in midair and planted his feet on the "ground." The gravity had been disabled in this elevator shaft. That had made traversing the many intervening decks easy . . . as long as he'd been willing to jump and trust that the power in this part of the ship wouldn't be restored.

The Engineer clutching his shoulder tapped the tiny control panel on the wall. The doors at the bottom of the shaft sighed and slowly slid apart.

Funny how the creature didn't care what or who John was. Didn't it know their races were enemies? It was clearly intelligent and could communicate. Maybe it didn't care about enemies or allies. Maybe all it wanted to do was its job.

There was a corridor ahead, five meters wide, with a vaulted ceiling. Past a final arch, the passage opened up into the cavernous reactor room. The ambient lights in the hallway and room were off. Along the far wall of the room, however, the ten-meterhigh reactor coils pulsed with blue-white lightning and threw hard shadows onto the walls.

The Master Chief adjusted his low-light filters to screen out the glow from the reactor. He made out the silhouettes of crates and other machinery. He also saw one of those shadows on the wall move ... with the distinct slouching waddle of a Covenant Grunt. Then the motion was gone.

An ambush. Of course.

He paused, listened, and heard the panting of at least half a dozen Grunts, and then the high-pitched uneasy squeaks the creatures emitted when they were excited.

This came as a relief to the Master Chief. If there was an Elite here, it would have maintained better discipline and silenced the Grunts.

Still, the Master Chief hesitated. His shields were gone, his armor breached. He had been fighting almost nonstop for what felt like years. He was forced to admit that he was at the limits of his endurance.

A good soldier always assessed the tactical situation—and right now, his situation was serious. A single lucky plasma shot could inflict third-degree burns along his arm and shoulder and incapacitate him, which would give the Grunts an opportunity to finish him off.

The Chief flexed his wounded shoulder, and pain lanced across his chest. He banished his discomfort and concentrated on how to win this fight.

It was ironic that after facing the best warriors in the Covenant, and after defeating the Flood, he could be killed by a handful of Grunts.

"Chief," Cortana said over the COM. "Are you there yet? I'm down to one last option."

The Master Chief replied in a whisper, "Almost."

"Be careful. Your armor is breached. You can no longer function in a compromised atmosphere."

He flashed an acknowledgment to Cortana and concentrated on the problem at hand. Using grenades was not an option; a plasma grenade or a frag near those reactor coils could breach the containment vessel.

That left stealth—and outwitting the Grunts.

Maybe he'd use his grenades after all. The Master Chief set a plasma grenade in the center of the elevator shaft. He took his remaining two frag grenades and set them aside as well. He felt along the elevator shaft walls and found what he needed—a length of hair-fine optical cord. He pulled out a three-meter length.

The Engineer gave a huff of irritation at this destruction.

The Master Chief threaded the line though the rings of his frag grenades and tied each end at anchor points ten centimeters off the floor. He wedged the grenades into the slot of the open door.

The trap was set; all he needed now was bait. He set a plasma grenade on the far wall of the shaft and triggered it.

He pushed into the corridor, fast. Four seconds to go. The gravity, still active in this portion of the ship, pulled him to the deck. He melted into the shadows and sprinted along the wall two meters farther in, and halted along the inside of the first support brace. Three seconds.

One Grunt emitted a startled cry and a plasma shot sizzled down the center of the hallway.

Two seconds.

The Master Chief pried the Engineer off his shoulder and pressed the creature firmly into the join where the brace meet the wall.

One second.

The Engineer squirmed for a moment, then stilled, perhaps

sensing what was about to happen. The plasma grenade detonated. A flash of intense light flooded the hallway and the room beyond.

The rest of the Grunts cried out; plasma bolts and a hail of crystalline needles filled the passage, impacting inside the elevator shaft.

The Grunts ceased fire. A lone Grunt cautiously stepped out from behind a crate and crept forward. It gave a barking, nervous laugh and then, encountering no resistance, waddled down the passage toward the elevator.

Four more Grunts followed, and they passed the Master Chief, oblivious that he hid behind the wall brace less than a half-meter from them.

They approached the elevator, sniffed, and entered.

There was the gentle ping as the frag grenade rings pulled free of the trip wire. The Master Chief covered the Engineer. One of the Grunts squealed, high and panicky. They all turned

and ran. Twin blasts of thunder enveloped the elevator shaft. Bits of meat and metal spattered along the corridor. A needier skidded to a halt a meter away. It was cracked, its

energy coil dim. The Master Chief grabbed it—ducked as another plasma bolt singed over his head. He withdrew to the cover of the bracing support. He tried to activate the weapon. No luck. 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 hundred needle-fine cilia and swept over the inner workings. A moment 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 except 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, unscrambling 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.