“Now there’s a good question.” Halsey rummaged in her bag and took out a water bottle. Mendez wondered if she’d hidden another sidearm in there. He wasn’t planning to give her weapon back to her until he was sure she wasn’t going to pul another stunt like the hijack. “This might not have been their only bunker, of course. It’s a big galaxy. But they’d stil want to be able to check outside before they opened the door. Perhaps even communicate with other shield worlds.”

“But who put the Katana and the other guys in the cryo pods?” Mendez asked. He wondered why he hadn’t worried about that detail sooner.

“Doesn’t that bother anyone?”

“Perhaps we should be asking why they decided to get into them instead,” Halsey said.

“Sounds like an assumption, Doctor.”

Mendez knew she hated that. She took a pul from the bottle and put it back in her bag, ignoring the bait. He stared hard at the leather, looking for an outline of a weapon, but the bulges just looked like women’s stuff and square-edged books or datapads.

“So let’s see what we find, Chief,” she said careful y.

Mendez checked his watch, wondering just how much out of sync with real time the Dyson sphere would be. Halsey gave the impression of being able to work out that kind of stuff on a napkin. He hoped she could. Could any of them real y know if time was suspended in here, like it seemed to be in those cryo pods? What did that feel like?

The crunch of boots on gravel and then on paving heralded Fred’s arrival with Lucy, Linda, Mark, and Ash. Fred had something in his hand.

Mendez’s reflex reaction was to wonder what the hel he was doing with tennis bal s, but then he realized Fred was clutching three spherical yel ow fruits one-handed. He held them out to Mendez.

“We ought to run tests on these first,” Fred said. “I’ve logged the location. Anyone got an assay pack?”

Mendez sniffed one of the fruits cautiously, picking up a faint smel of cedar wood. Its texture was like sticky suede, almost quince-like, but it wasn’t a quince. He hadn’t had to do this bushcraft stuff for years.

“Over to you, Doctor.” He handed the fruits to Halsey, who put them in her bag. “I’ve got some test strips for cyanogenic glycosides and alkaloids somewhere in my kit.”

“I’l take a look at them later,” Halsey said. “Let’s find a way to get into this tower.”

Fred motioned for everyone to move. “Okay, people, spread out and take a section of wal each. This tower first, then we’l try the other one. If anything opens, nobody steps in. Just cal it. I don’t want anyone stuck on the wrong side of a door we can’t open.”

The scale and lateral curve of the tower only sank in when Mendez began inching his way along his section of ashlars. He realized that he couldn’t see Mark to one side of him or Linda to the other unless he took a few paces back from the wal . He ran his hands over the stone, not sure what he was feeling for but expecting some kind of mechanism to detect him and either open a hatch or at least display some controls. Al the Forerunner technology he’d encountered so far did that kind of thing. But the wal remained steadfastly unresponsive.

“If you build a bomb shelter, you make it easy to find and get inside.” Halsey walked past him. She wasn’t searching the wal but pacing slowly along the paved perimeter with her eyes on the flagstones. “Imagine it. Things have gone badly wrong, the Flood is overrunning the galaxy, and al the Forerunners in the sector pile in here as fast as they can. No matter how advanced they were, they’d have needed to orientate themselves.”

“Then why not put the signs near the front door?” Mendez asked. “What if they never finished this place? Because they’re not around anymore, are they?”

Halsey said nothing but walked on, head down, the soles of her black loafers tapping on the flagstones. It was too easy to see the Forerunners as not simply advanced but godlike, just like the Covenant did. But Mendez knew al too wel that bril iant technology didn’t guarantee infal ibility.

Even humans hadn’t always thought of their own gods as being perfect, honest, or even competent.

“Ah wel …” He promised himself a few comforting drags on his cigar in two hours. The gold wal felt oddly warm and smooth under his fingers, like living skin. “Maybe we need to go back and check the portal area.”

Click … click … click.

“Jackpot,” Halsey cal ed. “Look.”

Mendez turned and jogged after her. Al the Spartans converged on the same spot. Halsey was standing with her weight on one foot, the other held a little off the ground as if she’d been frozen in the middle of playing a kids’ game of hopscotch. She’d looped the strap of her bag around both shoulders like a satchel, adding to the impression of a middle-aged schoolgirl.

“So this is what happens if you tread on the cracks,” she said.

Mendez stared at the flagstones. They’d come alive with pulsing il uminated symbols. A straight line of Forerunner glyphs, picked out in a soft blue light, led along the paving and curved up the wal to waist height. Halsey walked along the line. For al Mendez knew, it could have been a warning to keep clear. They’d find out the hard way.

“Can you read that?” he asked.

“It’s a sequence of numbers,” Halsey said. “But beyond that—no idea.”

She reached out and touched the top symbol. Nothing happened for a few moments, but then Linda and Fred swung around ready to open fire as if they’d heard something that Mendez hadn’t. He looked back at Halsey just as the wal above him split along a neat vertical line and parted al the way down to the ground. Nothing actual y moved; the stone blocks just suddenly vanished. In his world, doors that suddenly flew open tended to spew smal -arms fire.

The Spartans split instantly into two groups without a word and stacked either side of the opening, rifles ready. Halsey froze. Mendez reminded himself to give her his pistol.

“Steady…” Fred said. “Check first. Shoot later.”

Mendez moved around to face the opening head-on. He could see movement in his optics and his finger began tightening on the trigger. Then the movement resolved into gliding gray cylinders like the one that had swooped on them earlier. There were six this time. They moved out of the opening and arranged themselves along the wal at head height. Mendez wasn’t sure if they could detect weapons, but they didn’t seem to be making any defensive moves.

“So what are you?” Halsey murmured. One cylinder separated from the rest and came to a halt just in front of her face. To her credit, she didn’t even blink. “What are you monitoring? That’s what you’re doing, isn’t it?”

The cylinder moved from Halsey to Mendez, hovering so close that he felt it was staring into his eyes even though he couldn’t see a single damned detail on it. He held his breath until it moved away, smooth and silent, to hover in front of Kel y’s visor. She stood motionless with her rifle in one hand. Then she grabbed it, as fast as a chameleon ambushing a fly. It was so quick that Mendez didn’t even have time to flinch.

“Gotcha,” she said, peering at it.

The cylinder didn’t seem to be struggling. The other cylinders drifted away into the trees as if they had better things to do than hang around amusing humans.

“It feels like it’s not here. It doesn’t weigh anything.” Kel y flexed her gloved fingers around it. “Wow. This is the strangest thing I’ve ever felt.”

Halsey held her hand out and took the cylinder cautiously. She drew her chin in, frowning. “I see what you mean. That’s … wel , extraordinary.

Better hope I’m right and that it’s just some kind of recon drone.”

Mendez resisted the urge to touch it and see what al the fuss was about. “We’re stil making a lot of assumptions, Doctor.”

“Forerunner technology can recognize humans. So I’d cal it an educated guess.”

Lucy peered around the opening in the wal and Mendez gestured to her to cover him while he checked inside. He couldn’t see anything. Then the whole damn interior lit up like Christmas, flooding the wal s with lights and symbols from waist height to about five meters, reminding him of the control room of a power station. But it was completely, eerily, silent.

Lucy, just as silent, explored the chamber. It was about thirty meters wide but Mendez couldn’t see a ceiling in the gloom above. When he glanced back over his shoulder, Fred and Kel y were in the doorway, silhouetted against the daylight.

“There’s no way we can jam this open if it decides to shut,” Fred said.

Mendez felt they didn’t have much choice but to explore the place. “We’l have to take our chances.”

Then Lucy grabbed his forearm so hard that it hurt. He spun around. She made a shut-up gesture, finger to lower third of her visor, and pointed into the shadows on the left. The poor kid hadn’t spoken a word for eight years. But he knew how to listen to her. He held up a hand to stop everyone and edged forward.

Maybe she’d picked up something in her infrared filter. He stil couldn’t see anything. But then he heard it.

Something was moving away from them. It wasn’t a cylinder. It sounded like wet leather slapping against stone fol owed by the clatter of metal, getting fainter and almost echoing. Something was moving down a passage. The sound died away into silence again.

Mendez nodded at Lucy. Halsey crept up to him, ignoring the order to stay put, stil clutching the cylinder.

“What is it?” she asked.

“No idea. But that didn’t sound like the central heating boiler to me.”

“But we were the first in here. We activated the core room.”

“No, we just found a way in.” Mendez checked his ammo clip and headed into the shadows, stomach knotted tight. “But someone else found it first.”

UNSC PORT STANLEY, MIDPOINT ANCHORAGE, TEN MINUTES BEFORE JUMP TO SLIPSPACE: JANUARY 27, 2553.

Osman tried the CO’s seat on the bridge and felt smal and alone. She hadn’t expected that. It certainly didn’t give her a thril.

I’ve always been a spy in a blue suit.

She’d never felt like a real naval officer. ONI had taken custody of her as a fourteen-year-old, educated her, put her through the ONI commanders’ program, and reinvented her. She’d deployed in ONI’s fleet before, but she’d never had day-to-day command of a ship. Now she was going to find out the hard way if she could cut it.

Well, Parangosky thinks I can.… “In case you’re interested,” BB said, “I’m doing the final launch checks. Would you like me to spel them out?”

Osman couldn’t see him. She stared straight ahead at the disc of Mars, a smal rusty smudge framed in light-speckled blackness in the forward viewscreen. “I trust you, BB.” He could have left it al to the dumb AI, of course. “Where is everybody? Secure for launch.”

“The ODSTs are in the wardroom. They’re very excited about having their own cabins. I can tel from their bio signs. Poor little waifs.”

“Don’t stalk them, BB. It’s creepy.”

“Just monitoring, Captain. And Phil ips is checking out the crates in the cargo bay. I think reality has dawned on him. Are you happy having him embarked?”

“Not real y. Opsec worries.”

“Al comms go through me, Captain.”

“I meant when we get back.”

“Oh, I’l guarantee his silence. One way or another.”

“I’l bet.”

Osman suddenly needed something to focus on. She turned around in her seat because BB’s voice felt as if it was coming from behind her. He was, of course, everywhere at once; he was in every part of the ship’s systems, observing via every monitor and camera, control ing every aspect of its operation, in touch with Earth and able to hear and respond to any cal sign in the galaxy, omniscient and omnipotent—for the few years he had to live, anyway. An AI was a short-lived god. When she turned back to face forward, BB materialized a meter in front of the bulkhead.

“And where’s Naomi?” she asked.

“Heading this way,” BB said. “You might as wel tel her.”

The Spartan had been giving Osman odd looks al the way out here in the shuttle. Naomi seemed to realize she knew her but couldn’t place the face. Osman thought she’d changed a lot since her early teens, but some features didn’t alter with age.

“Yes, we’ve already got enough secrets to keep from one another.” Osman got up and stood facing the doorway onto the bridge, resting her backside on the comms console. “I’l tel the others too. If we’re running arms for Sangheili psychos, I suppose my status pales into insignificance.

No reason why I can’t, is there?”

BB moved around to settle in her line of sight. “The Admiral gave you carte blanche. Weapons free, repel al boarders, no prisoners, et cetera et cetera. Do whatever you need to get the job done … just don’t get caught, there’s a dear.”

BB had a rather arch way with him. Osman found herself smiling. Dear. Things were going to get very informal. She could hear Naomi coming now, the steady thud of her boots on the deck as she strode along the passage in that massively heavy armor she didn’t actual y need at the moment. Spartans had their comfort blankets too.

How would I have coped with the Mjolnir? Would I feel naked without it? Would I know where I ended and it began?

Naomi loomed in the doorway. She had that faint frown that said a memory was stil eluding her. “Ready to slip, ma’am?”

“Five minutes.” Osman realized BB had disappeared, or at least his avatar had. “Anything you want to ask me, Naomi?”

Using her name rather than addressing her as Spartan got a slight reaction. Osman noted a couple of rapid blinks.