He stood and said nothing.

"Very well. I suppose you know your limitations better than anyone else." She turned the display back around. "I wanted to speak about your report on the alien construct—Halo. I've pieced together a bit of the story based on Admiral Whitcomb's recounting of your adventures, Cortana's debriefing, and the mis- sion logs of Locklear, Johnson... and the curious partial mission log of one PFC Wallace Jenkins."

The Master Chief shifted uneasily.

"There are inconsistencies that I must resolve before we get back to Earth." She pushed her glasses higher onto the bridge of her nose. "One of them is Sergeant Johnson." She tapped in commands on her keyboard. "Please step closer, John. I want you to see this with me."

The Master Chief moved alongside her chair. His massive weight thudded through the thick deck plating. Two meters tall and half a ton of metal and somehow Dr. Halsey couldn't help thinking of him occasionally as the same little boy she had stolen from his parents in Elysium City.

No. John had changed. She hadn't. She was the one who still carried the three-decade-old festering guilt.

She took a deep breath and refocused her attention on the video records before her. On screen played mission logs that showed Covenant and Marines in firefights, the odd Forerunner architec- ture in the interior of the Halo construct, and the terrifying omni-parasitic life-form known as the Flood.

She replayed the mission record of Private Jenkins and the first Flood attack.

John stiffened as Captain Keyes appeared on screen and as the Flood consumed the Captain and his squad. Sergeant Johnson was there, too, fighting and cursing ... until the hordes of tiny, podlike Infection Forms swarmed over him.

"The Sergeant survived," she said. "The only human to have direct exposure to the Flood meta-organism and walk away."

"I know," the Master Chief whispered. "I'm not sure how he survived. How could anyone live through that?"

"That's the simple part," Dr. Halsey told him without looking up from her displays. She tapped a key, and the Sergeant's medical records flashed on screen. "See, here?" She touched a file dated three years before. "He was diagnosed with Boren's Syndrome."

"I haven't heard of it," the Chief said.

"I'm not surprised. It's caused by exposure to high-yield plasma. Like the burst released by a Covenant plasma grenade.

We don't see many cases—people usually die from the direct ef- fects of those weapons long before these secondary symptoms manifest.

"Apparently, the Sergeant captured a crate of plasma grenades from the Covenant during the Siege of Paris IV He used them all—received a commendation for bravery ... and a twelve-hundred-rad cumulative dose of radiation as an unanticipated bonus."

John was silent for several minutes. Dr. Halsey wasn't sure if he was reading the computer files, contemplating her words, or trying to confirm all this on a private COM channel with Cor-tana. His impenetrable armor made discussions with normal social conventions nearly impossible. It irritated her, yet without that armor with its constant hydrostatic pressure and automated biofoam injectors, John would have literally fallen apart by now.

For a fleeting moment she remembered when she had first read Alexander Dumas's Man in the Iron Mask. She had felt terror when the noble prisoner had been encased within that metal shell. How did John cope with the constant suffocating enclosure?

The Master Chief finally said, "I don't see the connection be- tween the Sergeant's sickness and his surviving the Flood."

"Boren's Syndrome," Dr. Halsey explained, "is characterized by migraines, amnesia, and brain tumors . .. and without the proper treatment, death. It disrupts the electrical signals in a person's nervous system."

"Is it treatable?"

"Yes, but it requires thirty weeks of intensive chemotherapy.

Which brings me to this." She hit the NEXT PAGE key and an official "Refusal of Treatment" document appeared on screen. "The Sergeant did not wait thirty weeks to get back and fight."

The Master Chief nodded, understanding the heroic, futile gesture. "How did this disruption of his nervous system save him?"

"I've deconvoluted the biosigns of the soldiers overtaken by the Flood. The parasite interfaces with a host by forcing a reso- nant frequency match to each host's neural system."

"And the Sergeant's nervous system is so jumbled that the Flood couldn't force a match?"

"Correct," she said. "Further blood tests show his system bearing traces of Flood DNA—very much dead and noninfec-tious, but some gene fragments are intact. I believe this is proof of a failed attempt to possess him. It also appears to have imparted him with some curious regenerative abilities, although I cannot yet fully confirm this side effect."

The Master Chief seemed to relax a notch from his usual ram- rod stiff at-attention stature. This new information seemed to put him at ease. "I think I see."

"No," Dr. Halsey told him, and she removed her glasses. "You don't."

"Doctor?"

"Discovering how he survived is not what I wanted to discuss.

It's what happens next to Sergeant Avery Johnson."

She shut off her monitors and eased back into the chair. "I've prepared two separate reports on this for ONI Section Three.

The first has all relevant data on my analysis and the possible technology to counter an initial Flood infestation. The second includes the source material: Private Jenkins's and Sergeant Johnson's mission logs and the Sergeant's medical files."

She downloaded the reports onto two data crystals and ejected them from the port on the chair's arm. She set the clear cubes on the tray and gestured for John to take them. "I leave it up to you which to deliver to Lieutenant Haverson."

"Why would I withhold any data, Doctor?" the Master Chief asked and glanced at the crystals.

Her eyes focused past him as she struggled to find the words to match her conflicting emotions. "For a long time I had thought that we had to sacrifice a few for the good of the entire human race." She took a deep breath and let it go with a heavy sigh. "I have killed and maimed and caused a great deal of suffering to many people—all in the name of self-preservation." Her steely blue gaze found him. "But now I'm not sure that philosophy has worked out too well. I should have been trying to save every single human life—no matter what it cost."

Dr. Halsey pushed the tray bearing the data crystals toward the Master Chief. "If you give ONI the first report, they may be able to find a countermeasure for the Flood. Maybe. They would have a slightly better chance, however, if you give them the sec- ond report."

"Then I'll give them the second report." He picked up the crystal.

"Which will murder Sergeant Johnson," she said with a chill in her voice. "ONI will not be satisfied to take a sample of blood.

They will dissect him to find out how he resisted the Flood. It will be a billion-to-one shot that they'll ever replicate his unique medical conditions—but they'll do it anyway. They will kill him because the trade-off is worth it to them."

The Master Chief picked up the other crystal and then stared at them both lying in his gauntleted hand.

"Is it worth it to you, John?" she asked.

He curled his hand in a fist and held it close to his chest. "Why do you want me to make this choice?"

"One last lesson. I'm trying to teach you something it's taken me all my life to realize." She cleared her throat of the lump thickening there. "I'm giving you the chance to make the deci- sion that I thought I couldn't make."

She glanced at the clock on her display. "I'm sorry. Linda is almost prepped for surgery, and I have several things I must accomplish before then. You should go."

The Master Chief obediently turned and strode toward the exit, but halted in the doorway. "Doctor, don't let her die again."

He then left the room.

Dr. Halsey watched until he rounded the corridor and was gone. She hoped she saw John again before she did what she had to do, but she might not. Would the thought she had planted within him take hold? The gesture might be the only thing she could do to atone for what she'd done to him and the other Spartans.

Such thoughts were luxuries when there were only three hours before Ascendant Justice exited Slipspace. There was too much to do before then.

She turned all the monitors to face her and typed in the com- mand to unsquelch Cortana.

"Lock the door," Dr. Halsey ordered Cortana. "Boost counter-intrusion measures to level seven."

"Done," Cortana said. The irritation at having been silenced for the last five minutes was like barbed wire in her voice. "What precisely was all that about? Teach the Master Chief a lesson?

Giving him a choice? Save one man instead of billions?"

Dr. Halsey ignored her and rapidly typed in commands on her keyboard. "Give me access to your core coordinates four-four-seven."

"Block removed," Cortana said with an exasperated sigh.

"Are you going to answer my question?"

"I'm tired of sacrificing others for the 'greater good,' " Dr.

Halsey replied. "It never stops, Cortana ... and we're running out of people to sacrifice." She tapped in a final command for the memory-wiping worm function and punched the ENTER key.

"What—"

"I'm erasing your files on this matter. I'm sorry, Cortana, but with this, I cannot trust even you."

Cortana was silenced as the worm burned through her memory and obliterated all inquiries and recordings pertaining to Ser- geant Avery Johnson.

"Cortana, give me an update on your core memory."

"Recompiling of routines has resulted in a memory-processing footprint reduction of sixteen percent, Doctor. Thank you. That gives me a little more room to think."

"I'm afraid that's all we dare risk," Dr. Halsey said. "The Halo and Covenant AI data could become corrupted if I do more. And there is no place safe enough to store that information."

Dr. Halsey loaded mission reports from Admiral Whitcomb's, John's, and Fred's teams. She frowned at the official UNSC inci- dent forms as their highlighted time, date, and location stamps scrolled across her screens.

"Are you done with the temporal analysis of these logs?"

"Yes, Doctor. You were correct: There is a discrepancy be- tween the Halo team and the team on Reach. The time stamps are off by an average of three weeks. I hypothesize that this was caused by my gravity-influenced Slipspace transition."

The corners of Dr. Halsey's mouth flickered into a smile. "I'm disappointed, Cortana. That's a guess ... and an incorrect one at that."

"Really?" Cortana replied with a hint of challenge in her tone.

"Do you have any data from your subsequent gravity-influenced translation to correlate?"

There was a two-second pause, and then Cortana finally an- swered, "Yes, Doctor. There are no temporal displacements on those later jumps."

"As I suspected." Dr. Halsey tapped her finger on her lower lip as she thought. "Plot the temporal irregularities on a space-time surface. Then call up my file on the spatial distortion generated by the alien artifact."

On the displays appeared two sets of nearly identical curved membranes that stretched about a central location and time: Reach and the recovery of the strange artifact.

"That thing not only bends space," Dr. Halsey whispered to herself, "but bends time as well."

"That's not possible," Cortana said. "How could the artifact on Reach affect us on Halo—light-years away?"

"Don't think of it as physical distance," Dr. Halsey replied ab-sentmindedly, staring at the monitors. "You and John were on an event path intersecting the crystal." She moved the curves over one another; the time and space surfaces were a perfect match. "You had to be there at that place and time to recover us and remove the crystal—time and space warped to make that event occur."

Cortana gave a derisive laugh. "That's circular logic, Doctor.

It directly contravenes several well-established theories—"

"And it fits the known data." Dr. Halsey shut down the files containing her analysis. "I see now why the Covenant are so interested in this object. They mustn't be allowed to get their hands on it. Not them, and certainly not Section Three, either."

"Doctor?"

Dr. Halsey turned to the screen with her memory-devouring worm and moved it to a new pointer in Cortana's core. She exe- cuted the program—destroying the AI's memory of this conver- sation, too.

"Give me an update on SPARTAN-058's condition, Cortana."

"Core temperature increasing at a steady point-two degrees Celsius per minute, attaining thirty-seven degrees in ten minutes."

"Very good. Prep and move the flash-cloned liver and kidneys from storage and ready surgical bay three."

"Aye, Doctor."

Linda's medical data winked on a display along with the entire Spartan roster: a long list of every Spartan's current operational status. Only a handful was left, almost every one of them listed as WOUNDED IN ACTION or MISSING IN ACTION.

"No KIAs?" Dr. Halsey murmured. She touched SPARTAN-034's entry. "Sam is listed as missing in action. Why would that be? He died in 2525."

"ONI Section Two Directive Nine-Three-Zero," Cortana re- plied. "When ONI went public with the SPARTAN-II program, it was decided that the reports of Spartan losses could cause a crip- pling loss of morale. Consequently, any Spartan casualties are listed as MIA or WIA, in order to maintain the illusion that Spar- tans do not die."

"Spartans never die?" she whispered. Dr. Halsey swiveled out of the contoured chair and pushed the monitors out of her way with a sudden violence. "If only that were true."

There was so much to do and so little time left for her, the Spar- tans, and the human race. She could do something, though. She'd save them one person at a time, starting with Linda, then Kelly, and then a handful of very important others.