Her Sacrifice

His plasma burns and other injuries were patched up in the ship's medical bay and he spent the trip home staring at Cortana's dormant holo-chip whenever he had a free moment. He kept her safe in a lead lined case when he wasn't staring at her. Compared to Human ships, it took The Relic no time at all to return to Earth. The Chief was welcomed home as a hero, much to his discomfort, and was awarded several medals he simply added to his collection.

He was immediately ordered to report to Dr. Halsey's laboratory after all of the usual UNSC debriefings, an order he had no hesitation in following.

"Chief, I heard she was still operational when The Relic found you…how is she?" Dr. Halsey asked after their initial greetings. It was somewhat odd seeing him out of the familiar MJOLNIR armor and wearing the standard issue grey UNSC T-shirt and slacks.

"Bad." He said and removed Cortana's chip from a lead-lined protective container and held it out to her.

Dr. Halsey frowned and took the chip, inserted it into one of her holo-pads and sat down in front of the computer connected to it. John stood by and waited while she tapped several keys on her keyboard and brought up several lines of code that made no sense to him at all. He simply waited patiently as she studied the strange characters on the screen.

The more Dr. Halsey read the more she looked surprised and baffled. "This is…well, I would say it was impossible if I weren't looking at the code myself."

"What is it?"

"This is incredible. I don't know how she did it, but she somehow reprogrammed herself. It's too soon to say for sure, but it looks like she dumped all her non-critical programming and deleted all her non-relevant data. This is extraordinary…."

"Why would she do that?"

Dr. Halsey's fingers tapped almost musically on the keyboard and she read over several more lines of code before she looked up at John, somewhat startled. "It appears…she did it for you."

"I don't understand."

"From what I'm looking at….all of her remaining programs, functions and memories all center around you." She pointed at a line of code he didn't understand. "This right here is her primary objective code. It's supposed to say that her primary objective is to serve the UNSC and the SPARTAN program. But she reprogrammed herself to only serve and protect John aka Master Chief Petty Officer aka Sierra-117. And her only remaining mission objective was to rescue you from the Forward unto Dawn." Dr. Halsey turned back toward the screen and studied it some more, wondering out loud "How on earth did she figure that out? There are measures in place to keep AIs from restructuring themselves like this…."

The Chief was silent while Dr. Halsey continued reading lines of code. After several moments it seemed she had forgotten his presence, or at least was paying him no mind. Finally he asked "Can you save her?"

The question startled Dr. Halsey. "What?" She turned and looked at him.

"Can she be saved?" He repeated.

The look on her face was answer enough. "Chief…I'm sorry. Even if she wasn't so fragmented…AI's only live for seven years."

He glanced significantly at the holopad housing Cortana. "She's nine." He stated by way of argument.

Dr. Halsey nodded. "Yes, but that's only because she figured out how to reprogram herself. She must have been going rampant…when AI's get that old they literally think themselves to death. But Cortana certainly knew that…it must be why she reprogrammed herself and made the extraordinary sacrifice to dump her extra data. It's really quite revolutionary, what she's done…most AI's are completely unwilling to delete any information, let alone the staggering amount she did. I've never seen anything like it. The data dump bought her time." She looked sadly at the holopad that housed Cortana's chip. "But only time enough to see you survive….she sacrificed her self to save you."

"…I didn't say 'we're being rescued' for a reason." Cortana's voice ghosted through his memories.

He couldn't let it end like this for her. "Find a way."

Master Chief began walking toward the door. Dr. Halsey shook her head sadly "Even if I could find a way, it would take years."

"…Anything for you, John."

He stopped at the door and looked over his shoulder at her…or maybe it was Cortana's holopad…she wasn't sure.

"She waited years for me." And then he left.

Dr. Halsey spent weeks going over Cortana's code and thinking about what the Chief had asked of her. Recovering an AI as damaged and fragmented as Cortana had never been done…the best anyone could claim was what she was doing now…going over lines and lines of their remaining code and extracting whatever data was needed, then destroying what little remained of the AI.

There had never been any reason to try to recover an AI before. AIs were expendable. Expensive, but expendable when it came right down it. They only lasted seven years after all, and the UNSC AI techs could directly remove any important data without regard to the "life" they were dissecting.

But Dr. Halsey had always had a soft spot for Cortana…she was modeled after her own mind after all. And Cortana's apparently deep attachment to John also struck a sympathetic chord with her. So despite her misgivings, she examined Cortana's code and tried to think of a way to recover her.

What she discovered as she uncovered more code, however, was not exactly what she originally thought or expected.

Cortana hadn't exactly "dumped" all of her memories not tied to the Master Chief after all. Some of them were too important to outright delete. So Cortana had compressed, firewalled and buried them into her code as best she could.

It turned out that as Halsey had suspected, Cortana had been hacking her way through the UNSC and other databases almost from the moment she was created. A great deal of the data was corrupted or lost, but Catherine soon figured out mostly what her "daughter" had been up to when no one was looking, and could make some educated guesses.

The most intact data had been about the first time Cortana had been paired with John during that "training exercise" and the resulting hacking Cortana did to get back at Colonel Ackerson.

To Dr. Halsey's profound shame a memory-file Cortana had preserved was about Dr. Halsey's first meeting (and subsequent abduction) of John when he was a boy, and all the records of the training and modifications he had to endure as he went through the SPARTAN program. She had no idea that Cortana had known.

Again, it was clear that the majority of the data Dr. Halsey was finding was centered around John. Not all, but a great deal of them.

She was beginning to wonder about Cortana's intense fixation with John when she uncovered a strange subroutine along with those buried compressed files that lead to a holo-message.

A message Cortana had left for John. At first Dr. Halsey was confused as to its nature. It was connected to a series of subroutines that she later found out would activate and play for him only if Cortana was not around to wake the Chief up herself…..and then Dr. Halsey realized why she had done this.

Cortana had left John a good-bye letter.

After watching the message, Dr. Halsey sat back in her chair, slightly stunned. And then she spent a good long while looking at Cortana's holopad, lost in thought.


AN: a slightly shorter chapter, I know. Third and (possibly) last chapter coming soon. Story may get bumped up to an "M" rating if I add a fourth chapter. Story gets a bit more AU after this.