"I think this guy's been here since the place was built," Mendez said. "Or at least his forebears were. At the risk of pissing you off again, Doctor, I've been here for more than twenty years, and ONI started rooting around the planet sixty years ago, so I doubt this fella's ever worked for the Covenant."

"If he's a direct descendant of the ones built by the Forerunners, then imagine what information he can give us. Just imagine." Halsey sounded breathless. Damn it, she was excited as a kid and trying hard not to show it. "Not that I know how long these constructs last when they're left to their own devices."

Constructs. Halsey liked her dividing lines between people and nonpeople. The Engineer finished with the datapad and turned it so that they could see what he'd done. They now had an audience of Spartans gathered around them.

MY NAME IS PRONE TO DRIFT. WE HAVE WAITED SINCE THE BEGINNING. WHY DID YOU ACTIVATE THE CITADEL WHEN THERE IS NO FLOOD?.

"Well, I guessed right about the Flood," Halsey muttered. "And he's rather socialized and assertive for a Huragok."

Mendez ignored her and concentrated on the Engineer. "How do you know there's no Flood outside? Can you get a signal out of this place?"

The Engineer went back to composing his response.

THE MASTERS LEFT BEFORE THIS WORLD WAS COMPLETED. WE WAITED BUT THEY NEVER RETURNED. WE HAVE DONE WHAT WE CAN, BUT WE HAVE NO FURTHER INSTRUCTIONS.

"I said can you transmit and receive signals from outside this sphere? And what's the problem with the date? What's upsetting Lucy?"

OUR SPACE IS OUTSIDE THIS ONE. FOR HER, IT HAS BEEN HOURS NOT DAYS.

Halsey's cheeks were flushed and her eyes sparkled like she'd fallen in love. Mendez wondered if she'd looked that way to Jacob Keyes or if she reserved her passion for objects and ideas. She repeated the question that Mendez had asked. "How can you tell what's happening outside this sphere?"

THE SENSORS TELL US. WE CAN VIEW EVENTS IN THE OTHER SPACES. WHY? IS THIS ABOUT THE WAR?.

"Yes, yes, that's it, it's about the war." Halsey took a step forward, right in the Engineer's face. "I'm a scientist. I need to know. And I need to let my people know that we're all right. Have you any way of transmitting a message into the other space?"

"Before we start transmitting anything I want to be sure where this guy's come from," Fred said. "I don't care if it looks quiet outside. We're not going to give away our position until we're absolutely certain what's going on."

Halsey raked her fingers through her hair, all impatience. "Well, it looks like we've got another slipspace bubble within this one. It's almost as if it's made up of concentric bubbles. Like a Russian doll."

Mendez glanced at Lucy, giving the datapad a meaningful look. Would she tell him anything more? Lucy took the hint, peeled the pad out of Prone to Drift's grip, and started writing. Mendez wasn't expecting what came next.

I KILLED AN ENGINEER, she said. SORRY.

The beginnings of an exasperated look formed on Halsey's face, but it didn't get any farther. Mendez glared at her. It was too damn bad about the Engineer, but they could always make some new ones. He couldn't make another Lucy.

Just thinking that reminded him what Halsey had done with cloning, and it was another rebuke about those things he'd turned a blind eye to when he should have turned her in instead. But he'd worry about that later. Halsey was already hassling the Engineer, demanding that he show her inside the structure.

Prone to Drift didn't seem much different from any human being who liked his job and was only too happy to show visitors around his office. He started floating back toward the tower with Halsey trailing after him.

"Linda, with me," Fred said. He went off after Halsey. "Let's make sure we don't lose her as well."

Mendez decided things were looking up at last. Now they had the best possible assistant for milking every scrap of technology out of this place and getting it back to ONI. He took out his cigar, lit a taper of grass with his fire steel, and inhaled a damn good lungful of sweet, soothing, luscious smoke. Halsey was going to be some time.

He looked over Lucy's remodeled backpack, wondering if Engineers ever left anything alone.

"And next time, Petty Officer, you will listen to the lieutenant's orders and you will follow them," he said, holding up a warning finger. "Because I don't want Dr. Halsey lecturing me on how you've all got poor impulse control."

It would have raised a laugh under normal circumstances, but they'd all lost too many people now. Just getting Lucy back in one piece seemed to be enough. For an hour, Mendez allowed himself the respite of sitting on the grass with the Spartans, picking over the leftover barbecued fish and contemplating when he'd be able to replenish his supply of Sweet Williams. The brief break came to an abrupt end when his radio crackled in his ear.

"Chief, you really need to come and take a look at this," Fred said. "And bring a tranquillizer dart to calm down Dr. Halsey. She's in hog heaven. Just walk down the corridor and you'll find us."

"On my way, Lieutenant." Mendez got to his feet and jerked his head at Lucy. She was now the Engineer wrangler, after all. "Come on, kid. Let's go see what the good doctor's found."

Fred might have been joking about the tranquillizer dart, but if Mendez had had one, he would have been sorely tempted to use it. Lucy seemed to know where she was going and led Mendez into the darkness. He felt something brush his arms and face as if he was pushing through curtains, and then he was suddenly in an enormous, brightly lit hangar faced in stone like everything else in this world. It was busy with at least a dozen Huragok drifting around an assortment of vessels that he didn't recognize at all.

He could hear Halsey calling him. "Chief? Chief, you won't believe what we've got here."

"I can see it, Doctor." He ducked under the fuselage of a large satin-gray ship about the size of a Pelican, but he couldn't tell if it was brand-new or if it had seen a thousand years' service. He followed the sound of Halsey's voice and stuck his head inside the first hatch he found open. "Is it just fantastically interesting, or is it actually going to be any use to us?"

Halsey's indignant face popped up right in front of him, almost making him flinch.

"Yes, just a little," she said. "You want to transform slipspace navigation? You want to know when you slip exactly where and when you're going to drop back into realspace, and not end up hours and millions of kilometers from your target? Well, it comes as standard on every damn model in this showroom. And we're going to have it."

Mendez thought of Kurt and the others with a strange kind of regretful relief, a realization that their lives had brought something priceless and hadn't been wasted. He decided he might crack a new cigar after all.

"Thanks, Kurt," he murmured. "Thanks."

CHAPTER.

THIRTEEN.

WE CAN'T FORGIVE, AND WE CAN'T FORGET. BUT THERE'S A THIRD OPTION WHICH ISN'T RELATED TO EITHER. IT DOESN'T REQUIRE US TO BE FRIENDS. WE CAN SIMPLY BOTH AGREE TO STOP KILLING EACH OTHER.

(ADMIRAL LORD HOOD TO THEL 'VADAM, STILL KNOWN AS THE ARBITER) MAINTENANCE AREA, FORERUNNER DYSON SPHERE, ONYX: LOCAL DATE NOVEMBER 2552.

Halsey communicated with Prone to Drift with an ease that Lucy envied.

The Engineer seemed to have picked up an understanding of spoken English with typical speed, and all Halsey had to do was keep her datapad focused on his tentacles while it relayed the conversation back to her in a neutral male voice. It was a quick exchange of software and algorithms, nothing like the painful, primitive steps that Lucy had had to go through to communicate with Prone.

Halsey looked excited even though she was putting on her I'm-a-detached-professional voice. Lucy noted the way she kept licking her lips like she was desperate to interrupt with new questions.

"But can that slipspace navigation be adapted to fit human ships?" she kept asking. "Look, I've got some schematics here." She brandished the pad. "Can we achieve that degree of insertion accuracy?"

"If your drives are sufficiently responsive," said the flat, disembodied voice emerging from her datapad. "We need to examine one."

"We can fetch a whole fleet here for you to play with," Halsey said. Lucy watched Mendez roll his eyes very slowly and then look away. The rest of the Spartans were wandering around the hangar, examining the Forerunner vessels. "All we have to do is get a message out to my people."

"We are not in your time," Prone said. "And there is something out there."

"What do you mean, something out there? You told me there was no evidence of the Flood and the Halo hadn't fired."

"There is something out there that is both there and not there. It may be a threat. Are you not interested in the condition of the Reclaimers in stasis?"

He meant the Katana personnel and the unidentified civilians. Lucy felt ashamed that she'd been too tied up in her own problems to ask Prone to open their slipspace pods.

"We're interested in them," Mendez said. "Why are they in there? What happened?"

Prone paused for a moment. Lucy wasn't sure if Engineers were capable of lying, but they were definitely sensitive to agitation and seemed to want to avoid upsetting humans.

"We went to the portal when the first shield procedures activated," the proxy voice said. "They are too damaged for us to repair. We placed them in stasis for those with greater knowledge to attend to them."

So Team Katana were either dead or dying, and the Engineers had done the only thing they knew; they put them on life support and waited for the medical experts to show up. But the Forerunner medics were never going to come. Lucy hoped that Halsey's medical genius was all it was cracked up to be and that she could do something for the Katana guys, even though she seemed to think of them all as substandard merchandise.

"Explain what you mean by not in our time," Halsey said. "I realize this is a slipspace bubble, but exactly how far out of sync are we with the galaxy?"

"Varies," the virtual voice answered. "And can be varied. If the other space talks to you, it hears your reply fifteen or twenty times later."

Halsey seemed to be struggling to pin Prone down to terms she understood. She tried another tack.

"Can you tell me the date in the human calendar on the outside? Access my datapad again. Extrapolate from the calendar we use."

Prone reached out and fluttered his cilia over the datapad. "The year division is two-five-five-three. The lesser division is two."

Lucy was now used to Prone's turn of phrase, and understood that as February 2553. They'd been here days, yet months had elapsed outside. But what was out there waiting for them?

Mendez took a couple of steps forward and eased himself into the conversation. "Now I'm really grateful that you brought Lucy back to us," he said. "But is there any way you can let us signal one of our own ships so we can take her home?"

"Until we know if the object is a threat, we must remain concealed." Prone seemed to be getting jumpy. His lights were growing more intense. Lucy wanted to step in and defend him, to stop Halsey demanding so much of him. "We cannot repair Lucy-Bravo-Zero-Nine-One. Somebody must."

"We'll take care of Lucy," Mendez said. Halsey looked as if she was going to interrupt but seemed to realize that Mendez was making a better job of the diplomacy. "What would it take to make you feel things were safe outside?"

"To identify the object as nonhostile. To make contact with our own kind for verification. Or for the Forerunners to return."

Mendez stared at the floor, fists on his hips. "Well, we might be able to manage at least one of those. But I'll tell you now that the Forerunners disappeared a very long time ago, son."

Prone's bioluminescence flared again and he floated away to join the group of Engineers huddled in the corner of the hangar, watching the strange newcomers messing around with their vessels. He seemed to be breaking the bad news to them.

"Got to feel sorry for those poor damn things," Mendez said. "Imagine waiting patiently all those years for the boss to show up and then being told that he's dead."

Halsey drew in a breath. Lucy didn't expect her to give a damn about the Engineers' feelings and the woman didn't disappoint her. She just went right on talking at Mendez, stabbing a finger for emphasis. "Chief, do you understand how important this technology is? This slipspace navigation alone-it'll give us a major tactical advantage over the Covenant. And God only knows what other technology we'll find when we've finished going through this place. I don't care what it takes, but we have to let people know what we've got in here."

"And then what? How do you crack open a Dyson sphere and get it back to the right dimension or whatever you call it? If those Engineers can't or won't do it, then we're screwed." He looked at Lucy as if he expected her to offer an opinion. "And what the hell is out there that's spooked them so much?"

Prone drifted back to them and stopped in front of Lucy. "Our orders are clear. We must maintain this shield world until the Forerunners have need of it. We will do that."

"How many other shield worlds are there?" Halsey asked. "Where are they?"

"Many, but we have no information."

"Where did the Foreunners go?"

"I cannot tell you."

"And there are other Halos in the Array, are there?"

"There are six left in this galaxy."

It was more a cross-examination than a discussion. Lucy wanted to step in and slow things down, but she didn't know how. But that was vital information.

Halsey's tone softened like a parent asking her five-year-old what he'd done with Mommy's keys. "Prone to Drift, do you know where they are?"

"No. The charts were located in the other places." Prone folded his tentacles close to his body, looking as if he'd had enough of the interrogation and couldn't work out what this woman wanted. Lucy couldn't decide whether he was being evasive or whether it was just a glitch in the translation. "When will you repair Lucy?"

"I'm not sure anyone can repair her," Halsey said. "Please, we need to talk about calling our people. If you can make contact with the outside world, then you owe it to us to do it. It's your duty."

"You are not a Forerunner," Prone said.

"You said we were Reclaimers."

"There is something waiting outside."

Halsey turned to Lucy, frustrated and tight-lipped. "Lucy, you seem to get on with the Huragok. Make them understand how important this is."

Lucy couldn't make them do anything. And Prone could hear this going on, of course. Did Halsey think he was deaf?

"I've still got some questions to ask him," Mendez said. "Anyone mind if I have a chat?"

"If he has sensors that can detect something outside this sphere, there's got to be a vector by which we can get a signal out," Halsey said. "I'll go look around and see what I can find."

"Yeah, but mind you don't piss them off, Doctor," Mendez warned. Halsey stalked off. "Just don't go barging in and upsetting them. Dr. Halsey, did you hear me?"

Halsey moved between the vessels, looking around as if she was trying to find an exit. She must have seen the main passage leading to the workshop, because she jerked her head around and strode purposefully in that direction. A couple of the Engineers detached from the group and drifted after her.

Lucy looked at Mendez and shook her head.

"Yeah, I know," Mendez said. "We're dependent on the goodwill of these guys." He tilted his head back slightly and looked at Prone as if he was trying to do the man-to-man thing. "Prone, do you think the war is over? What makes you think that? Because we've been fighting an awful long time, and if it's over, I've got friends I need to check on. Make sure they're still alive."

Halsey had gone off with her datapad, so Mendez wouldn't get a response from Prone that he could understand. He still tried. Prone looked at him intently, head bobbing, then turned and headed after Halsey.

"Come on, Lucy," Mendez said. "I might have to drag her out of there to keep him happy."

Prone could put on a fair turn of speed when he wanted to. He zipped ahead, vanishing down the passage, leaving Lucy and Mendez to jog after him. Lucy could hear the conversation long before they turned the corner. Halsey was looking for the comms controls, and Prone didn't like it.

"Just show me what's out there," Halsey said. "I'm the chief scientist for the human armed forces. Do you understand? I may be able to tell you what's out there."

The datapad voice took over again. "No. We must maintain silence."

"Do you seriously think that whatever's out there isn't curious about a Dyson sphere? What kind of anomalies do you think it's causing outside? It's an environment as big as a solar system compressed into a small ball. Whoever's watching won't get bored and go away."

"We have our instructions."