He moved to the still-open port hatch, slid the fiber-optic probe outside, and plugged it into his helmet. Grainy images ap- peared on his heads-up display.

Hundreds of Covenant ships swarmed into view. In their midst a speck glowed and grew larger until the Master Chief saw it was a ship of similar design to their own: two U-shaped hulls, each the size of their dropship, sat on top of one another. This ship accelerated toward them and separated—one part moved to their dropship's stern and the other drifted to the nose.

The clanging of metal on metal reverberated through the hull, and the Master Chief felt a gentle motion in the pit of his stomach.

He looked back and passed on a thumbs-up to Fred, indicating that their tow had arrived, and Fred passed this signal on to the rest of the team.

On the fiber-optic feed the Master Chief saw that the Covenant tug maneuvered them through the fleet, up, over, and around ships a hundred times their size. There was a moment when they dived and there was nothing on screen save the stars and black of space. The Master Chief got a glimpse of the gold-colored star on his heads-up display, and then the video feed moved over to a planet of ocher smeared with clouds of sulfur dioxide and an or- biting moon of silver.

The tug turned to face a new ship in the distance. This vessel looked like two teardrop-shaped Covenant ships that had collided, giving the result an overall elongated figure-eight geometry.

They moved toward this ship, and the Master Chief made out more details. Spokes radiated from the narrow midpoint of the vessel and connected to a slender ring that he hadn't seen before because they had approached facing it edge-on. Featherlike tubes extended from either bulbous section and moved slowly over that central wheel. John squinted to make out more details on this unusual ship, but he was already at maximum resolution.

It had a ring? Was it rotating? But the Covenant had gravita- tional technology. They didn't need rotating sections to simulate gravity.

Then he saw something recognizable on the structure: tiny ships docked to that ring. Covenant cruisers and carriers. There must have been sixty connected to the central hub.

The titanic perspective of this structure clicked into place.

The carriers looked like toys. The twin teardrop shapes had to be thirty kilometers end to end. This could only be the Covenant command-and-control center, the Unyielding Hierophant.

The tug moved directly toward the station. It was precisely where they had to go, so it was a lucky break... but ironically, it was also the last place the Master Chief wanted to be.

There was no telling what kind of sensors the Unyielding Hiero-phanthad, but they couldn't take chances. John retreated into the dropship and eased the hatch shut.

He moved deeper into the ship and waited with the rest of Blue Team.

Three minutes ticked by on his mission clock; John tried to control his breathing and focus his mind.

Gravity settled his stomach, and there was a series of metallic clatters along the hull. Atmosphere hissed in though the cracks of their breached ship.

John pointed at Fred and Grace and then to the starboard hatch. They leveled their rifles and moved. He pointed to Linda and himself, then the port hatch, and they also moved into position.

John wasn't sure what kind of reception waited for them on the other side of those hatches, but one thing was certain—they'd have to face it head-on. There was nowhere to hide inside the re- inforced and too-cramped interior of their dropship.

The port hatch cracked and squeaked open.

Linda and John aimed their rifles.

CHAPTER THIRTY-THREE

0610 hours, September 13,2552 (revised date, Military Calendar) \ Aboard Covenant battle station Unyielding Hierophant.

A rubbery tentacle reached in along the seam of the drop-ship's hatch.

John raised his hand and signaled Linda to stand down. He recognized the alien limb—the splitting cilia feelers and globu- lar sensory organs could belong only to a Covenant Engineer.

The Engineer pushed open the hatch and entered the ship, floating past John and Linda as if they weren't there. It chittered and squawked as it ran its tentacles over the foreign armor plates and spatters of lead. Two more Engineers bolted through the open hatch and joined the first.

As long as they left the single-minded aliens to their work, they wouldn't raise an alarm. But what else was out there?

John eased against the frame of the hatch and slid the fiber- optic probe outside. There was a line of dropships, Seraph fight- ers, and other singleships that stretched away into the shadows.

Swarms of Engineers, thousands of the creatures, hovered and drifted throughout the area. They moved parts, disassembled and reassembled sections of ship hulls, and plumbed plasma coils. There was no trace of a welcome party of Elites waiting for Blue Team.

John turned the optic probe up and saw a latticework deck overhead with tools, welders, and spotlights hanging like jungle vines. It was as good a place as any to get their bearings.

John turned and pointed at Linda and Will, then out the hatch and up. They nodded and moved out.

Five seconds later acknowledgment lights from Blue Four and Three winked on. It was safe for the rest of them.

John grabbed the upper lip of the hatchway and flipped up onto the top of the dropship. He grabbed a dangling cord and pulled himself onto the latticework deck where Fred and Linda perched, watching and making sure the bay was clear.

Grace and Fred disembarked and scrambled silently up into the darkness, joining them.

John pointed two fingers at his eyes and then made a flat fan motion across the space of the bay. The Spartans moved to care- fully scan the area.

From his shadowy overview John saw that this place was a repair-and-refit facility, with slots for hundreds of singleships.

The room curved out of view three hundred meters in either di- rection. It must run the circumference of the station's hub.

Apart from the thousands of busy Engineers, John spotted only two Grunts wearing white methane-breather masks. It was not a color designation he had seen before. They pushed carts containing barrels of sloshing fluids. They would be easy to avoid.

One side of the bay had a series of sealed doors that he pre- sumed led to air locks. The opposite wall of the bay had a meter-thick window through which poured an intense blue light.

Every thirty meters along that transparent wall was a recessed alcove. Overflowing from the nearest alcove were purple poly- hedral cargo barrels, old charred plasma coils, and plates of the silver-blue Covenant alloy. But what piqued John's interest was what was next to this pile of junk: a holographic terminal.

John clicked his COM to get Blue Team's attention, pointed to the junk pile, held up two fingers, and then pointed again at the alcove.

Everyone nodded, understanding his order.

Fred and Linda silently dropped to the deck, ran across the bay, and melted into the shadows behind a cut section of hull.

Grace followed.

John looked up and down and side to side across the bay, mak- ing sure no Grunts were visible. He and Will crossed and took cover behind a plasma coil the size of a Warthog light reconnais- sance vehicle.

He used both hands to point at Fred and Linda, turned his hands so they pointed to himself, and then nodded to the data terminal.

Linda lay flat and slithered to the edge of the alcove shadows on his right; Fred took the left. They would cover him while he moved to the terminal.

John reached to the back of his neck and pulled Cortana's chip from his skull. He crawled on his stomach, hugging the wall until he got to the terminal. He slid Cortana's chip into the input slot and then eased back into the shadows.

"I'm in," Cortana reported over the COM. "I have secured our own channel and encrypted the signal so we're free to use the interteam COM."

"Good work," John told her. "Is there a central reactor in this station? How well defended is it?"

"Stand by. I have to move carefully. There are Covenant secu- rity AIs in this system."

John hoped that this copy of Cortana's infiltration routines was as good as the real Cortana.

"I have schematics for the station," she told him. "The good news is, each lobe has a central reactor complex with five hundred twelve-terawatt units similar in design to the pinch fusion reactors on their ships. Apparently this energy is used to power a shield generator that can repel the collision of a small moon. I can overload one reactor, causing the melting of its field coils, which will saturate the surrounding—"

"Will it explode?" John asked impatiently.

"Yes—an explosion of sufficient force to vaporize both sections."

"That's the good news? What's the bad?"

"The reactor's control system is isolated. I cannot reach it from this terminal. You will have to physically deliver me there."

"Where is 'there'?"

"The nearest reactor-control access point is seven kilometers farther into the station's top lobe."

John considered this. If they were careful and lucky, it might be possible.

"Is there a way to leave you in the central system until we need you?" he asked. "It would be handy to have you monitor the Covenant security systems."

The duplicate Cortana was silent a full three seconds. "There is a way," she finally replied. "When I was copied from the original Cortana, the duplicating software was copied as well—it becomes an inseparable part of all subsequent copies. I can use this to copy myself into this system."

"Perfect."

"There are risks, however," Cortana told him. "Each successive copy contains aberrations that I cannot correct. There may be unforeseen complications associated with using a copy of a copy."

"Do it," John ordered. "I'll take that chance. But I'm not willing to take a chance on crossing seven kilometers behind enemy lines without a way to bypass their security systems."

"Standby," Cortana said. "Working."

A minute ticked off John's mission timer. Then the data chip ejected from the terminal.

"Done," Cortana said over the interteam COM. "I'm in. There's an exit to this bay thirty meters to your left. I will black out the security cameras there and open the door in twenty seconds.

Hurry."

John retrieved the chip and reinserted it into his skull. There was a flash of cold mercury in his mind.

"Move out," John told Blue Team. "Stay low."

Fred's and Linda's acknowledgment lights flickered, indicat- ing the way was clear.

Blue Team ran, crouching, for thirty meters. A small access panel slid open, they piled through—then the door snapped shut behind them.

They proceeded, hunched over; they crawled on their hands and knees, on their stomachs, and through ducting so tight they had to shut down their shields and scrape by on bare armor over metal. For kilometers they followed Cortana's directions, halt- ing as she ran motion sensors through diagnostics until they passed ... twisting and turning and shimmying down long lengths of pipe, dodging the giant blades of circulation fans, and edging by transformer coils so close that sparks arced across their shields.

According to John's mission timer they had followed this route for eleven hours—when it dead-ended.

"New welds," Fred said, running his gauntlet over the seams in the alloy plate blocking their path.

Cortana broke in over the COM, "It must be a repair not logged into the station manifest."

John said. "Options?"

Cortana replied, "I have only limited mission-planning rou- tines. There are three obvious options. You can blow the ob- structing plate with a Lotus antitank mine. You can return to the repair bay where we might find a less obvious way in. Or there is a faster, alternative route, but it has drawbacks."

"Time is running out," John said. "The Covenant aren't going to stick around much longer before they strike Earth. Give me the faster route."

"Backtrack four hundred meters, turn bearing zero-nine-zero, proceed another twenty meters, and exit through a waste access cover. From there you will move in the open for seven hundred meters, pass through a structure, and then down a guarded corri- dor to the reactor chambers."

Grace interrupted, "What do you mean 'in the open'? This is a space station; there should be no open spaces."

"See for yourself," Cortana said.

A schematic of the "open space" appeared on their heads-up displays. John wasn't able to make much sense of the diagram, but he could tell there were several catwalks, buildings, and even waterways—as Cortana indicated, lots of open areas for them to be seen in.

"Let's take a look," John said.

He led his team back the way they had come and pushed open the waste access duct. Blue light flooded the tunnel. John blinked and let his eyes adjust, then pushed the fiber-optic probe through the opening.

John didn't understand what he saw—the optical probe must have malfunctioned. The image looked impossibly distorted.

But there was no motion nearby . . . so he risked poking his head out.

He was in the end of an alley with walls towering ten meters to either side, casting dark shadows over the waste access hole. A group of Jackals passed the mouth of the alley only five meters from his position. He ducked ... and none of the vulturelike creatures saw him in the dark.

When they passed he looked up and saw that the fiber-optic probe had not been broken after all.

The space station was hollow inside, and a light beam shot lengthwise through its center: a blue light that provided full day- light illumination. Along the curved inner surface were needle-thin spires, squat stair-step pyramids, and columned temples. Catwalks with moving surfaces crisscrossed the space, as did tubes with capsules that whisked passengers. Water flowed along the walls in inward-spiral patterns and then waterfalled "up" into great hollow towers that sprouted from the opposite wall.

Banshees flew in formation through the center space of the great room, as did flocks of headless birds and great clouds of butterflies. It could have been an Escher etching come to life.

John felt extreme vertigo for a moment. Then he understood that with advanced Covenant gravity technology, there didn't have to be an up or down here.