Onward with the crossover magic! As always, I'd love to know what you think! :D :D

Cortana was on Reach.

Here, in this perfect recreation of her home, she could forget that she and John were in some unknown universe, trying to protect humanity from the atrocity of the Halo ring.

Here, she could almost imagine having a conversation with Doctor Halsey about ONI and their ridiculously stringent protocols.

Here, she could forget that she is dying.

Here, isn't real, of course. But the Enterprise's holodeck makes it very convincing and almost allows her to forget everything that happened on the bridge.

Almost.

When the captain had ordered her and John off the bridge while he and the rest of the senior staff had a meeting, she had transferred herself to the holodeck where most of her program had remained, working on getting her back to functioning properly. She hadn't even told John she was leaving.

The yellow grid that awaited her was too oppressive for her, so she quickly created a familiar environment for her to work in. In original Sword Base, she had worked with the doctor to achieve greatness. She hoped she was able to achieve that once more.

As she walked through the halls of the holographic base, she stepped through the doors to Halsey's lab. The interface in the center of the room was still tied to the Enterprise's main computer. She accessed the information and frowned. The progress was going slower than she would have liked.

She was tempted to blame the slower computer, but she knew that most of the problem lay with the amount of corruption in her files. It was amazing that she had even been able to be reactivated.

Commander Data was the one to thank for that. She and he had implemented the positronic protocol to her matrix. It took a bit of work to get the two differing technologies to be compatible, but they had finally got them to communicate with each other.

Maybe she would be able to complete this mission with John, after all.

She hadn't expected that she would ever see him again. After their last mission, after she had almost failed to protect him, she had resigned her fate that her second chance to work with the Spartan was over.

But somehow, she made in here.

The doors to the holodeck opened. John walked in, helmet on his head.

Creating a holographic interface to buffer her systems, instead of relying on John's helmet, had been her first priority after she had been activated on the holodeck. It was too difficult -too distracting- to see John's face as Data rambled on about their idea to salvage her program.

It wasn't the worry or concern that bothered Cortana.

It was the unabashed hope on his face.

Within minutes, she had created the interface and John had his customary helmet in place.

He crosses the room to stand next to her. "You left in a hurry."

"Well, I am busy trying to save my life here."

"Data said he's optimistic." There was a slightly hitch to his voice.

"Everyone on this ship is optimistic, but that doesn't mean that his plan is going to work either," she said, averting her eyes. She didn't want him to see the hope reflected in them.

"It will work." Classic Spartan determination.

"What if it doesn't?" She looked at him, grateful for the reflective visor. "We both know that I shouldn't even be here, John."

"But you are."

"Because you saved me. Or part of me anyway." She crossed her arms. "We both know that what you found after the Composer's destruction is only a fragment of what I used to be."

He took a step closer to her. "You are still Cortana."

"But for how long?" The question caught in her throat. She drew in a breath, forgetting for the moment that it was completely unnecessary and looked at him squarely. "If I die, you have to continue the mission without me. Promise me."

The air in the room got heavy as the weight of her demand pressed upon them.

"I can't."

"What happened to you, John? The man I knew would give up anything for a mission's success, no matter the cost."

He doesn't answer right away. When he does, his voice is quiet. "I learned that sometimes the price is too high to pay."

"John..."

He reached over and put his hand on top of hers. She let out a soft gasp. He never sought out any sort of physical contact from her. "Don't ask me to make a promise that I won't keep. I cannot do without you, Cortana. I've tried."

She knew he had. She twisted her hand around so she could give his a gentle squeeze. "I don't want to say goodbye again," she whispered.

"Then, don't." He nodded towards the console she had been working on. "We'll get you back to normal and then we'll complete our objectives. Together."

"You make it sound so simple. Saving the universe."

"We've done it before."

She raised an eyebrow. "If wasn't for your lack of a cape, I might think you're some kind of superhero or something."

"No. Just lucky."

Her eyebrows furrowed. There was a whisper of a memory that was just out of her grasp. "I said that to you once, didn't I?"

She felt his hand stiffen under hers. "Yes. On the Cairo platform."

Cortana didn't want to admit that she didn't know what he was talking about; that still so many of her memories were locked away in the chip, more than likely too corrupted to ever be of any use. She offered a smile that she hoped didn't look as forced as it felt and pulled her hand away.

"I should get back to work. We have no idea what if the captain is even going to let us stay aboard if his little meeting with his staff."

"He will." John sounded confident.

"But what happens if he doesn't let us get down to the surface?" she countered.

"We'll figure out a way. We always do."