Authors Note: Like the summary explains, this is the backstory to the Master Chief's entrance into my main fic, Halo: New Horizons. If you have not read that, I highly suggest you stop on by.

This by no means will take the place of New Horizons, I will still be updating that story as often as I can.

In regards to the recent plot developments in Spartan Ops, for the sake of this story this is all you need to know.

- While Halsey was present on Requiem for some time, she didn't go all crazy with the Librarian and that whole business.

- Lasky, Infinity, Blue team, and the rest of the Spartans are currently on an exercise somewhere else.

I'd really appreciate it if you took the time to review and tell me what you think.

Enjoy.

Disclaimer: I own nothing, but all original content is mine.

Chapter One: Back to Work

Cairo Station, Geosynchronous Orbit above Earth, February 18th, 2559

"Doctor, I just want to know if she's going to be alright."

Doctor Catherine Elizabeth Halsey quickly looked up from the work she was conducting in her laboratory.

"I've already told you, I don't know." she said, slightly annoyed. Remembering who she was talking to, Halsey apologized, letting out a deep breath.

"I'm sorry, I didn't mean to snap at you. I've been under quiet a lot of stress lately."

"It's okay ma'am, I understand." she heard.

"A recovery and reconstruction procedure of this scale, and with so little to go on, has never before been attempted. In my honest opinion, I am not sure if it is even possible."

Halsey looked at the man in his hard, dark blue eyes. He looked like he hadn't slept in a few days, that much was evident by the red eyes and the slight bags under them.

"John, I know how much Cortana means to you, and while it may be a longshot, I'll do my best to bring her back."

John-117 nodded absentmindedly, looking at the table Halsey was working at. On it were thirty-seven, he had counted four times, pieces of metal, circuitry, and other assorted debris. However, this wasn't any ordinary debris. UNSC teams had spent the better parts of two years sifting through the wreckage of the Didact's ship Mantle's Return for anything of value, and when sensors had discovered a number of ghost traces consistent with a UNSC A.I., the search had kicked into overdrive.

Those thirty-seven fragments represented the last bits of Cortana left in existence, and Doctor Halsey was going to try to put them back together.

Halsey put a hand on John's arm, she might as well have been touching rock due to the Spartan-II's incredible physique.

"John, this is going to take several hours to complete. Go, get some sleep, I'll come get you when it's over."

Never taking his gaze off of the fragments, John nodded absentmindedly, then turned his massive frame towards the door and walked out into the lobby.

Seeing a chair against the wall, the Spartan collapsed into it, feeling it groan under his weight. Leaning his head back against the wall, he reminisced on the past two years since the Didact had been defeated. He had been granted a generous amount of shore leave, but after a couple of days wandering around aimlessly at military bases, he requested to be put back to active duty.

And so he was. The Master Chief was sent all over quelling insurrectionist movements, battling the Storm Covenant, and he even served a couple more tours on Requiem. Yet he went about all of these tasks with the monotonicity and mechanical-like precision of a robot. Even after he was re-united with Blue team, things just weren't the same. Although he felt more than comfortable fighting with his fellow Spartan-II's, there was always the feeling that there was something missing, like a squadmate was left behind. Despite being offered the chance to work with other AI, he flat-out refused to do so, always shifting the burden to another.

Even Kelly, who has been one of John's closest friends, had told him that he was becoming cold, detached, and she was right. He tried his best not to be, but he couldn't help it, he just didn't have the heart.

John remembered what Captain Keyes had said to him on the Pillar of Autumn, "Get Cortana off this ship. Keep her safe from the enemy." It had been his responsibility, his duty, to protect Cortana from harm, and he had failed at that.

"Soldiers aren't machines. We're just people." Chief thought back on the words Lasky had said to him after the Didact had been defeated. Lasky was wrong, at least about him. John was a soldier, and he would always be one. He would never be a regular person, never live a regular life. His life was on the battlefield, and would be until he was dead.

The Spartan took a deep breath through his nose and closed his eyes. It had already been two years, he could wait a few more hours...

"Cortana? Cortana, do you read? Cortana, come in." John said into the comm.

John turned around and saw Cortana striding towards him. Her body was made out of hard light, and she was as tall as a real human being. They walk towards each other.

"How...?" he asked, dumbfounded.

"Oh, I'm the strangest thing you've seen all day?" said Cortana, smirking.

"But if we're here-"

"It worked. You did it. Just like you always do."

Cortana smiled, and John looked around bubble curiously.

"So how do we get out of here?" he asked.

Cortana looked down a little gravely.

"I'm not coming with you this time.

John furrowed his brow in confusion. "...What?"

"Most of me is down there. I only held enough to get you off the ship." she said.

"No. That's not-!We go together."

"It's already done."

"I am not leaving you here."

"John..." Cortana walked up to him and touched his breastplate, the spot glowing in response.

"I've waited so long to do that." she said, sighing.

John looked away. "It was my job to take care of you."

"We were supposed to take care of each other. And we did." she said.

John looked up at her, and Cortana sadly smiled.

"Cortana- please..." John begged.

She began to back away, out of the bubble.

"Wait," he pleaded

"Wake up John." she said.

"Wake up."

"John! Wake up!"

The Master Chief's eyes snapped open and he flew out of his chair, instinctively bringing his sidearm up and scanning for targets.

It wasn't until he saw a very startled looking Doctor Halsey quickly backing away when he realized he was still on Cairo Station and was not in any immediate danger.

"Doctor Halsey, I'm sorry. I did not mean to scare you." said the Chief.

"No, it's quite alright," Halsey replied. She started to smile, and said, "I believe I have something you'll want to see."

She then reached into a pocket in her labcoat, and withdrew a crystalline datachip, the semi-transparent inner circle glowing a faint blue.

John looked at the chip, then back to Halsey, who now had a full-blown grin on her face, small crinkles showing at the side of her mouth.

"It worked John, we did it. The recovery was a success."

As if on que, a holographic avatar of a blue-tinted woman jumped out of the chip, using it as a base to 'stand' on. She smiled and waved a code-lined hand at the Spartan.

"Hi John."

The Chief was at a loss for words.

"Cortana." he said after a few seconds of silence.

Suddenly, Chief could hear a door opening, and he turned his head to the noise.

Decades of military instinct automatically kicked in, and John snapped to attention, whipping off a perfect salute.

"Admiral Hood, sir!" he bellowed.

Dressed in his white Admirals uniform, Hood kept walking until he was standing in front of the Chief, and he returned his salute.

"At ease soldier," he said. Looking towards Halsey he continued, "Doctor Halsey, and.. Cortana? It's good to see you back. I apologize if I'm interrupting, but something's come up."

"What is it sir?" asked John.

"A new mission soldier. If you accept, you're to depart immediately. Details will be given en route." Hood explained.

John turned to look at Cortana.

"Ready to get back to work?"

Cortana just smiled at him again. "I thought you'd never ask."