They didn’t go out for long, though.

He wasn’t on the surface any longer. He was standing in a stone-lined chamber with passages leading off it on al four sides, evenly lit, and each wal bore rows of engraved symbols. It was too quiet for him to know if the chamber was insulated from exterior noise or not, but he could hear nothing.

“Prone,” he said. “Prone, where are you?” He shouted in case the communications device had failed, although he doubted Huragok handiwork was that unreliable. “Prone! ”

There was no answer. He pressed the smal device but there was stil no response. He had no idea where he was, no idea of how he’d arrived here, and he wasn’t sure if this was a disaster or a way out. Only one thing was clear: he couldn’t stand here indefinitely. Al the passages looked much the same, so he made a note of some of the most noticeably different symbols on each wal by scratching them into his belt with his nails. At least he’d be able to tel which passage he’d already walked down if he retraced his steps.

“Prone? Can you hear me?” He walked down the passage to his left. The wal s were mostly plain, precisely made blocks with velvet-smooth surfaces, but some bore rows of symbols or even rectangular panels with a few single symbols within their margins. They looked very like the carvings on the ruins around Mdama. Eventual y he came to a dead end and stared at the wal for what felt like a long time, mesmerized by the symbols and what they might mean. Why put them down here? What were they supposed to do?

Why hide them down here?

He was guessing the intent of ancient aliens whose technology was stil far beyond anything modern societies could create. He was doomed to fail. Now he could hear a slapping sound that he recognized. Prone was rushing down the passage. He’d found an entrance, then. Now he could explain to Jul how he’d ended up down here.

Jul half-turned and reached out to touch one of the panels, more to feel how precise the edges of the inscribed symbols were, and then his comms device came alive.

< Don’t. Don’t touch the panel.> Jul’s fingers brushed it just as Prone gave the warning. The next thing Jul knew, Prone had cannoned into him and wrapped his tentacles tightly around his arm. Prone pul ed Jul backward so violently that he felt a tendon rip. He landed flat on his back, winded, and his head cracked against the stone floor. For a moment he lay stunned. It wasn’t just the force of the impact. It was the shock of being flung across the room by a Huragok. His reflex was to leap to his feet and strike down whoever struck him, but he was too shocked. It was like being struck in the face by a female. These things didn’t happen. They just didn’t happen.

Prone was like al Huragok, utterly passive, focused to the point of fixation on technology and repairing it. Some would become very agitated if Forerunner artifacts were damaged, and he’d heard of some Huragok defending their brothers against physical threats, but they didn’t start fights.

Jul turned his head to make sure that Prone wasn’t going berserk with some form of technology that nobody had imagined. He could see the Huragok huddling by the wal . For a moment he thought Prone was cowering from him, expecting punishment, but then he realized he was actual y shielding that wal —the wal that Jul had been told not to touch. The creature’s bioluminescence was now vivid, brighter than normal, a sign that he was afraid or stressed.

Jul had no idea Huragok were so strong. But then they had to handle machinery, and nobody ever asked them if they needed a hand. It had never occurred to him to wonder how strong they had to be to do that, even though it was staring him in the face: very strong indeed. Because their bodies were sacs of gas and they floated, it was easy to think of them as delicate and fragile. Forerunners were masters of design, able to defy time and space, and more than capable of combining delicacy and immense strength in one structure.

And a servant that powerful could only be control ed if they were designed to fol ow instructions closely and without argument. One of those must have been to use extreme force only in the most serious situation, even more serious than saving their own lives. Jul had simply never asked the question before, and never seen what was right before his eyes.

< Are you damaged? > Prone asked. < I didn’t intend to harm you. More harm would have been done if I had let you touch this. > “What did I do?” Jul asked.

< I warned you not to touch the panel. The portals don’t work as designed. There are none of us at the terminals to maintain them. > “You said they didn’t work.”

< I said they no longer worked properly. I said that none could come here. > “So they go somewhere, but not where they were intended to go?”

< Which is very dangerous. > “I’m sorry.” This was an incredible change in Jul’s fortunes. And in this structure, he was effectively shielded from Prone’s device, as wel as out of sight of the surveil ance drones. Magnusson couldn’t find him here. Even so, he needed to pursue this line of questioning very careful y.

“Prone, I didn’t mean to upset you. But they’d only go to other Forerunner structures, surely.”

< Some intended destinations we know. Some we were never allowed to know, only that they were there for those who had supplementary information.> Anywhere else was better than here—unless a portal took him into the heart of another artificial star, of course. Jul got to his feet with slow care, making no attempt to move toward that wal .

“And you’re not al owed to tel anyone what you do know.”

< No. You mustn’t tell the others. I shouldn’t have lost you and let you near this. > “I don’t want to get hurt. And I won’t tel Magnusson.”

< Good. > Jul folded his arms to make it clear that he wasn’t going to touch anything. He fol owed Prone to the surface, but stil wasn’t sure how he ended up back in the sunlight. Something brushed his face again and he was instantly outside.

He would memorize this place. This was his way home—somehow. And he hadn’t had to search for years to find it. If it was dangerous, then he’d face that risk.

Prone stopped and peered at Jul’s belt, head bobbing up and down. His tentacle snaked out and touched one of the symbols Jul had etched into his belt.

< Why did you inscribe that? > “In case I needed to find my way back. Why?”

< Do you know what it means? > Jul was intrigued, but tried not to look too interested. He had to assume he was back under surveil ance now. “No.”

< That’s something you must avoid,> Prone said, turning around again. < Never touch it.> “Why?”

< The Didact, > Prone said. < Hidden even from us. Hidden when the Librarian made her sacrifice. > Prone said nothing more during the long walk back. If he was seeking to quash Jul’s curiosity, he’d gone about it entirely the wrong way.

UNSC INFINITY, SANGHELIOS “Bandits at twelve o’clock, Wing Co,” BB said. “Break, break, break.”

Hood ambushed Osman as soon as she got out of the bridge deck elevator. She carried on walking down the passage, but there was no way past him: he was a big man and he could block a lot of passage.

Her heart rate hiked for a few seconds. BB felt it via her earpiece. “Haven’t you got a dark blue version of that?” she murmured.

“No. But the phrase ‘If I cannot sink her, I wil ram her’ springs to mind.”

It was hard to blame Hood, real y. He was only doing his job, which was keeping one eye on the Sangheili, one eye on ONI, and … wel , that was the problem with humans. They were one eye short, at the very least. Hood needed to keep another eye that he didn’t have on the colonies, too.

“Captain,” Hood said, al charm. “Margaret’s being very coy. Successful hunt?”

“You won’t be getting any more trouble from Kig-Yar, sir.” Her heart rate didn’t so much as blip this time. “Not with our own munitions, anyway.

Pious Inquisitor is another matter.”

“Let me be specific. Did you find and destroy that unidentified ship?”

If she wanted to end the conversation, she’d have to actual y brush past Hood. To her credit, she stood her ground and stil managed not to actual y lie, merely put him in a position where he’d have to cal her a liar.

“Sir, I’d need to check up on the law regarding opening fire on pirate vessels crewed by a former enemy with which we have no official peace treaty.”

“You missed your vocation, Captain.”

“Have we got a treaty with the Kig-Yar?”

“No.”

“Best not trouble the Judge Advocate with that thorny issue, then, sir.”

Hood’s smile set solid. “We’re going to have a lovely time when Margaret retires.”

“Very kind of you to say so, sir.”

She returned the smile and carried on to the bridge. Thanks to Port Stanley’s detour, this wasn’t going to be a hot wash-up. It had already cooled to lukewarm. Everyone had had a chance to get their stories straight so that events would be tidied up rather than uncovered and learned from, which BB decided was just as wel . He felt relaxed enough to manifest himself and drift along behind Osman instead of lurking in the systems and whispering in her ear. She real y did need to start letting people know she’d been in the Spartan program, just so they ful y understood who they were dealing with. What a lovely piece of theater it would have been to have her pul his chip out of her neural implant in a meeting; she already had al the cerebral connections in place, and it was just a matter of talking her into having the Huragok create a special external interface and letting him download into it.

But I’d better make sure that I’m fit enough to wander around in her brain first.

What’s she done with the radio?

It was stil in her pocket. He’d kicked the dilemma around for ages—ages even by human standards—but if he wanted the data from the temple at Ontom, he had to interface with his fragment. And Phil ips kept saying how important it was. The Prof had a lot of images on his datapad, but nowhere near as much material as the fragment had recorded. Every detail counted.

Halos. He’s sure it’s the locations and operational status of the remaining Halos. If Mal and the others are willing to take a bullet for Earth, I should be, too. Virtually speaking.

Parangosky was talking to Phil ips when Osman walked onto the bridge. He was getting his pat on the head for being a clever boy, and he was giving her a heavily censored briefing. These were al the little things that made humans … human. They had the technology to dispense with conversations, finding things out the labor-intensive way, or ever lifting a finger. The likes of BB could do al that for them. They didn’t need to talk to one another or eat actual food, but that was just existing, not being alive. BB understood al that in a way he’d never realized he would.

Phil ips stopped talking and looked expectantly at Osman.

“We’re just discussing whether to visit the Arbiter or let the Arbiter visit Infinity, ” he said. “Or just waving from a distance and asking him if everything’s okay, because we’ve got to be going. It’s a Sangheili psychology thing.”

“He’s won this round,” Osman said, “and the other keeps have decided to keep their powder dry. But how do we exit this?”

“Wel , he’s seen some of the hardware we can now deploy, so it’s a choice between looking supportive, and not hanging around to provoke Sangheili who already think he’s a human-loving traitor,” Parangosky said. “Evan thinks looking submissive by offering the Arbiter the choice would achieve more than being assertive this time.”

Osman shrugged. This was a sideshow for ONI and they al knew it, but for Hood it was serious diplomatic hassle. “Are you seriously going to let him on board, ma’am?”

“This place is the size of a city. Why not? We can confine him to the atrium. He doesn’t get to see Huragok, he doesn’t get to see anything sensitive or conspicuously unfinished, he doesn’t run into anyone he shouldn’t, and he gets a lovely view of space. Much as I’d love to mooch around down on the surface, Evan thinks that would tip a few keeps over the xenophobic edge. Anyway, it’s Terrence’s cal .”

BB occupied himself while the grown-ups had their discussion. He took a tactful strol around Aine’s databases—clean as a whistle, no incriminating evidence or problems there—and tried to resist taking another look at Catherine Halsey.

Hiding people from most of the crew was something you could only do on a very big vessel, and the engineering section seemed to be a very effective oubliette. BB sneaked into the engineering mainframe and watched Halsey from her own terminal for a while, trying to feel pity now that she’d had plenty of time in solitary to dwel on the death of her daughter. He didn’t manage it. She looked tired and resigned, so he doubted that she only lived for the thril of discovery; there was probably nothing worse for a human than having no shoulder to cry on, and Halsey had savaged or frozen al those offered to her throughout her life. BB wondered how Osman would react if he told her how often Halsey cried herself to sleep, but just tel ing her that would probably erode a little trust between them.

I’m a spy. I spy on people. I don’t spy on my own team, though. I keep an eye out for them, and I don’t intrude unless they’re in trouble. I hope Osman understands that.

Parangosky dragged him into the conversation. “So how are you doing, BB?”

“I’l tel you when I’ve reintegrated, ma’am.”

“If you need some technical support, you-know-who would probably be fascinated to help.”

Halsey was the expert in third-generation smart AIs, even if she’d never worked on a fourth-gen one like him. He didn’t doubt her technical genius. But asking her for help wasn’t without its downside. He had a conscience, and he also had a healthy fear of handing over his brain to a sociopath with a record of terminating AIs.