“I need you to link with the flagship’s intraship battlenet,” the Chief cut in. “When we’re close you’ll need to shut down its weapons. Jam its communications.”
	...
	“Connecting to the Covenant battlenet,” Cortana announced over the ship COM. “Accessing their weapons systems. Stand by.”
	...
	“Forward weapons systems and shields are disabled,” Cortana said.
	...
	“I can’t do much good in there with you. Once I’m directly in contact with the ship’s battlenet, however, I can infiltrate and take over their systems. You’ll still need to get to the bridge and manually give me access to their engineering systems. In the meantime, I may be able to control secondary systems and buy you some time.”
	...
	Cortana was built for software intrusion. She had been programmed with every dirty trick and code-breaking algorithm the Office of Naval Intelligence, Section Three had ever created, and a few more tricks she’d developed on her own. She was the ultimate thief and electronic spy. She slipped into the Covenant system.
	It was easy the first time she had entered their network as the Longsword had approached the flagship. She had set their weapons systems into a diagnostic mode. The Covenant had determined the problem and quickly reset the system, but it had given Polaski the precious seconds her sluggish human reflexes had needed to get inside the launch bay.
	“How is it?” the Chief asked.
	Now the element of surprise was gone, and the system’s counterintrusion systems were running on high alert. Something else prowled the systems now. Delicate pings bounced off the edges of Cortana’s presence; they probed, and withdrew.
	It felt as if there were someone else running through their system. A Covenant AI? The possibility of one nearby intrigued her.
	“It’s…different,” she finally answered.
	She scanned the ship’s schematics, deck by deck, then flashed through the vessel’s three thousand surveillance systems. She picked out the quickest route to the bridge from their current position and stored it in a stolen tertiary system buffer. She multitasked a portion of herself and continued to analyze the ship’s structure and subsystems.
	“Proceed thirty meters down this passage and turn left.”
	Cortana hijacked the external ship cameras and detected the six Covenant cruisers. They had stalled their pursuit of the Longsword and now hovered a hundred kilometers off the flagship’s starboard side. The strange U-shaped Covenant dropships launched from the cruisers and swarmed toward the flagship. That was trouble.
	Within the flagship she spotted a dozen Elite hunter-killer teams sweeping the corridors. She scrambled the ship’s tracking systems, generated electronic ghosts of the Chief and his team along a path directed toward the nose of the ship, where UNSC command-and-control centers were typically located. Maybe she could fool the Elites into a wild goose chase. She uploaded the coordinates of those enemies into the Chief’s HUD.
	...
	Cortana had to focus on protecting the Chief. She halted her other searches and scrutinized the ship’s schematics. There had to be something she could use. A weapon. A way to stop their enemies—there: the backup terminus for their atmospheric preprocessors. Unlike the other systems, this one was classified as low priority and had minimal security layers.
	She generated several hundred thousand Covenant codes in a microsecond and cracked the system. She diverted the air vents along the corridors the Chief and his team occupied to the primary air systems. She then tasked the processor pumps to service the rest of the ship and activated them—in reverse.
	Warnings flashed throughout the Covenant system as the pressure suddenly dropped in 87 percent of the ship’s passages. She squelched them.
	The other presence in the system tried to shut the pumps off. She blocked that signal and assigned a new code to the security systems: “WE REGRET TO INFORM YOU .”
	She heard the other AI scream, an echo of an echo that reverberated through her processors. She knew the sound—familiar like a human voice, but terribly distorted.
	She scanned through the ship’s cameras and saw Grunts squeal and fall over, methane leaking from their breathers as the pressure dropped. Engineers turned blue, slowed, and died, floating in place with tentacles twitching, still searching for something to fix. The Elite hunt-and-destroy parties halted in the corridors and clutched their throats, mandibles snapping at air that was no longer there; they toppled and suffocated.