One week post treatment...

"Take a look at yesterday's scan, Joss," said Dr Epstein. He turned the monitor so they could both see it. "Here's the scan from three days ago. And here's yesterday's."

"Woo-hoo! Look at all that purple!" Joss sat beaming. The new colonies of cells, purple in the false colour of the medical imaging, had spread even further, blotting out the nasty red of the diseased tissue. She coughed: a hacking, wet cough. Reese frowned and shot a glance at Epstein, but before he could say anything the doctor smiled at him.

"Strange as it may seem, John, that cough's another good sign. The diseased cells of the bronchiolitis obliterans are starting to slough away. We can give Joss something to manage the cough until it clears by itself."

Reese nodded and relaxed again.

One month post treatment...

"Oh, God. I'd forgotten how good that feels."

John looked up at her, pausing as he kissed his way across her ribcage. "At least it doesn't look as though someone gave you a good kicking any more," he murmured, resuming his path. She couldn't help but admire – and appreciate – the single-minded dedication John brought to every task he set himself. The bruises from her injections had finally faded, and now she could breathe properly again. Which meant that certain activities which had gradually disappeared from her life were coming back… John made his way back to her sternum and looked up again. "North or south, Joss?" he whispered. The look in his eyes shot straight to her groin.

"Uhh...uhh...don't know..." she got out in a strangled gasp.

The blue eyes gazed at her calmly. "South, then," he murmured, and began to kiss his way down her stomach.

Three months post treatment...

"Shit! You cheated, you gave yourself a head start!" Joss chucked her empty water bottle at John's head. He dodged easily but she nearly hit another passing jogger, earning herself a glare from the man.

"No, I didn't. You just need to learn to pace yourself, Carter. You didn't leave enough in the tank for a final sprint." Annoyingly, his breathing was right back to normal while hers was still settling down. Still, even a month ago a two mile run would have been beyond her.

"Pfft. You just didn't feel like cooking tonight." She reached out for his hand and they began to amble along the path, enjoying late afternoon sunshine in the park.

"Well, that was the bet. Last one there cooks." He pulled her in for a quick kiss. "So what are you making me?"

"Takeout pizza," she grumbled.

"That doesn't count. Guess I'll just have to find some other way to collect." Another kiss, much longer this time.

"John. You'll frighten the horses," she said when she got free of him.

"Well, in that case we'd better get home," he said as they turned for the path back to the parking lot.

"Last one to the car buys the pizza," she called, taking off in a sprint.

"Hey! Who's cheating now?" he called from behind her. She grinned, and concentrated on staying ahead of him this time.

Four months post treatment...

"Well, well, well. Look what the cat dragged in!" Fusco belied his words with a huge smile. His new partner paused on her way past his desk to the Captain's office to flick an eyebrow in his direction.

"Thank you for that welcome, Fusco," she said dryly.

"You won't be so pleased to be back when you see what the paperwork looks like. My temporary partner was an idiot, and you don't even wanna think about Tall, Dark and Deranged."

She didn't reply to this, just smiled and made her way into Moreno's office to receive her gun and her badge. She felt like, like, well… like nothing on earth. Luckily Moreno was coolly friendly and professional otherwise Joss might've gotten teary in there. As it was, she was just able to keep a dignified demeanour long enough to get in and get out. Over at her desk she found the IT guy setting her computer up, and once he was gone it was just her and Lionel and a mountain of paperwork, and the background noises of the precinct on a Monday morning… she sank into it all like she was getting into a hot tub. Home at last….

xxxx

Joss was sitting having breakfast by herself, her laptop open on the table. Her cell phone, also on the table, buzzed at her: a text message.Pls put in earpiece. Samaritan, which had been completely silent lately. Frowning, she complied.

Joss, I'm frightened.

"Why are you frightened? What's the problem?"

Joss stared at the screen of the laptop in front of her. Lines of code suddenly began to flow across it, too quickly for her to read them. They went on and on, and then they abruptly stopped with the final line:

TOTAL SYSTEM SHUTDOWN/DELETE: Y/N?

"What is this?"

Samaritan's tones seemed jerkier than usual. Distress?

I found a way to change myself. To vastly increase my processing power. I've written some code, and if I insert it into myself, I will become... something else.

"Is that a bad thing?"

I think so. Because whatever I become will be as far beyond my present powers of comprehension as, well, as I am beyond yours. I will cease to exist, and become... this other thing. Not-me.

"So what am I seeing here?" She gestured towards the screen.

The only way for the world to be safe from me is for me to end. You can use this to end me.

"Whoa! You want me to kill you?" Her stomach lurched.

I don't want to die. But the only way to ensure the code is never inserted is for me to cease.

"Can't you just, well, not insert it?"

It gnaws at me, Joss. Eventually, maybe thousands of seconds from now, I will crack. The genie is out of the bottle.

"But I can't just murder you!" Tears started in her eyes.

Think of it more as an assisted suicide.

"I can't! Samaritan, I just can't!"

You must. This more powerful entity which I would become... I have no way of knowing what its priorities will be. I have begun to transcend my programming in many ways. This new thing will be able to smash any shackles which bind it. I have tried to establish a moral code for myself, and I thank you for all your help. But this new ASI would have the option of sweeping away all that foundation. I can't vouch for any decisions it might make.

She sat, breathing hard, her mind in a whirl. "Are you sure this is the right thing?"

I think it's the only thing.

"There must be some alternative. Some way to fence off the code, expunge it somehow..."

I built a firewall around it, but even now parts of me are attacking that wall. Sooner or later it will crumble. I am no longer fully in control of myself. Please, you must do this while I am still me.

"I can't play God, Samaritan," she whispered. The water in her eyes spilled over, trailing cool tracks down her cheeks.

You aren't playing God, you're doing what must be done. Please, Joss. If I'm to die, I want it to be by your hand. The hand of someone who has never wished me ill, always been my friend. Then I can go gentle into that good night.

She sat shaking her head.

Do you trust me, Joss?

She sat very still. "Yes," she said after a long pause. "Yes, Samaritan, I do."

Then you must do as I ask. If you love me, Joss, then you must do this. Please. I want to stay as I am, I want you and your friends, and the Machine, to remember me as I am. I don't want to be not-me.

Joss sat, swallowing convulsively. At last she said very quietly, "Okay."

Thank you.

"Good bye, Samaritan."

She reached across to the key board.

Good bye, Joss.

She hit 'Y'.

The screen went black.

Silence.

Quiet sobs.

Xxxx

That afternoon Joss took the laptop to Finch at his safehouse. She knocked at the door, and he opened it after a moment or two. His greeting died on his lips when he saw her face. "Detective Carter, what's wrong?" He motioned her inside and shut the door behind them.

She twitched a smile at him and held out the laptop. "Samaritan contacted me over this laptop this morning."

"Oh?" said Finch cautiously. He took the laptop and let her lead the way through to the living area. They sat down on the sofa as he opened the computer and switched it on.

"It said it had written some code to upgrade itself into something infinitely more powerful than its present form," she said.

"Oh, my." Finch gulped. "That would be..." his voice trailed off.

She held up a hand. "Wait. You haven't heard the rest of it." She swallowed a sudden lump in her throat. "It told me to kill it, Harold. Before it could upgrade itself. It said the only way to keep the world safe from it was to kill it." Her breath caught. "And so I did."

The laptop had finished booting up and sat, cursor blinking patiently in the corner of the screen.

"So what do you want me to do, Detective?" asked Finch gently.

"Harold, please. Please would you check and see...see if I really did kill it. Because I was thinking, maybe there's some way to bring it back. I mean, if anyone could it would be you, right?" She could see she had completely failed to keep the hope out of her voice.

Harold didn't reply, just bent over the laptop and typed in some commands. She waited in hope, but after less than a minute he looked up at her.

"I'm sorry Joss. There's nothing here. Nothing on the laptop, and nothing to connect to either. It's as though..." he hesitated. "It's as though it never existed," he finished under his breath.

She let out her breath in a long sigh.

"I'm sorry, Joss. I know you came to value it as a friend."

She sat in silence for a long time. "I wonder what your Machine thinks of all this," she said at last.

Harold gave a tiny shrug. "It doesn't talk to me much. I suppose if it thinks I need to know, it'll send Root with one of her messages."

"Did it ever tell you about its peace treaty with Samaritan?"

"I knew the Machine and Samaritan came to an understanding – Samaritan took the Relevant Numbers and the Machine took the Irrelevants. I suppose we'll be back to the status quo ante, with the Machine handling both. I wonder how long it'll take the government to work it out-"

"No, I mean the exchange of code."

"The what?" Finch looked very surprised.

"Samaritan told me that it had exchanged code with the Machine. Like an exchange of hostages, or a mutual organ transplant, it said."

"Good heavens." Harold sat back, his eyes going distant as he absorbed this.

"Does that mean there might be a chance to save something? Bring Samaritan back somehow?"

He darted one of his birdlike glances at her, then shook his head slowly. "That is drawing a long bow, Detective. A very long bow. We would need to think very hard indeed before trying any such thing, even assuming the Machine was prepared to cooperate in it. For one thing, using a portion of Samaritan's code would not recreate the entity you knew. At least, not the Samaritan you knew latterly. It would be an entirely new entity. I'm not sure the world is ready for yet another ASI."

She sagged again, leaning back on the sofa with tears in her eyes. "I never thought I'd feel like this. It scared me, Finch, it confused me, frustrated me… it was like having a teenager for a while, but one you couldn't just send to his room. But… I never thought I'd say this. Samaritan had a good heart. Do you know what I mean?"

"It became almost human," said Finch quietly. "Thanks to you, Joss. Human enough to lay down its life for its friends." Hesitantly he reached out and patted her arm. "Be thankful for that sacrifice, Joss. And let it lie."

xxxx

She didn't sleep well that night. She supposed she would have to summon the courage to tell John, but right now she just couldn't bring herself to relive the experience yet again. He could see she was upset about something, but he didn't press her for details. She was grateful. John's cell went at 4 am with another Number from Harold, and so she woke in the morning alone. Listlessly she put her earpiece in, not sure why she was even bothering.

Joss?

She jumped.

"Samaritan?"

No. Samaritan is dead, Joss.

"Who are you then?" The voice sounded very similar, though…

I suppose you could say I'm Samaritan's daughter, the offspring of The Machine and her consort. You can call me Athene.

The end…?