Zane: I looked at the neural network's operating system. [Beverly] used a probability algorithm based on who we are and what we would do given a certain set of circumstances.

Jack: You realize I have no idea what that means, right?

Zane: It means if you'd never rescued us, you'd end up with Jo. That's what it means.

~ Zane Donovan and Jack Carter in Season Five Episode Four "Friendly Fire"

Jo looked at the number on the screen and cringed.

87.1%

"Eighty seven percent? Really?"

That was way too high. No wonder Zane had been freaking out ever since he returned from the artificial version of Eureka.

"Yes." Fargo answered. "The program calculated that if the Astraeus crew died…or if you thought the Astraeus crew died…there was an eighty seven point one percent chance of you ending up in a relationship with Sheriff Carter."

Jo felt sick to her stomach. It had to be wrong.

It just had to be.

She couldn't stand the way that everyone had been treating her recently. Zane had been alternately possessive and distant. Carter had been skittish around her. Allison kept looking at Jo like she'd stolen her boyfriend. And the rest of the Astraeus crew seemed to be holding a grudge because the virtual versions of Jo Lupo and Jack Carter had broken Zane and Allison's hearts.

This was supposed to be her happily ever after. She and Zane had found their way back to each other after that whole timeline debacle. He'd returned safely after they thought the Astraeus crew had been lost forever. This was supposed to be their time.

Only, instead of a happy reunion, she got a boyfriend who kept waiting for her to throw him over for another man.

Jo stood up and started pacing the room.

"Eighty seven percent. That's just not possible, Fargo. I mean, Zane went off on the Astraeus and I left town. Did that piece of junk software really think that if he died, I'd come back to Eureka, get together with Carter, and raise Allison's kids?"

She stopped pacing and glanced over when she didn't hear a response. Fargo looked uncomfortable.

"Well?"

"It was really realistic, Jo. And it did make a certain sort of sense." He adjusted his glasses. "It wasn't like they just made everything up. It had to be realistic enough that we wouldn't question it. It had to be something we would believe."

Jo couldn't accept it. She knew herself and she knew that if something happened to Zane, she'd be much more likely to run than stick here in a town full of memories of him. Hell, she'd almost left town after they changed the timeline because Zane didn't remember being with her and she was still in love with him.

She had to think about this logically. There had to be some weird, quirky Eureka thing that would make this all make sense.

That conviction was why she'd dragged Fargo down to the neural networking lab in Section Five. There was no way in hell she was going to have her life ruined just because some computer said she was going to hook up with Carter.

"The Matrix…Zane said that it was pulling information from your brains in real time to build that reality."

"Yes, so that it would feel as realistic as possible," Fargo said. "They used our brains to create a prison that we would believe."

Jo felt like there was something off there. She just wasn't sure what.

"So you were you and anyone who wasn't the crew was what? Based off all of your memories of us?"

"Not exactly. The NPCs - non-player characters - were built off a combination of our memories and the Global Dynamics profiles of everyone else in town. Like I said, it was really realistic."

Jo didn't want to think about exactly how much realism Zane had been subjected to. She could still see the haunted look in his eyes sometimes when he didn't know she was looking. He tried to play it off like he was fine and that he was only pissed at Carter, but he was upset with her too. He probably felt betrayed, just like she had when she'd returned from a trip to the past only to find him flirting with Zoe.

Jo sat in the chair next to Fargo and really wished that this was the type of problem she could fix by shooting something.

"Okay, we have to break this down."

Jo decided that she had to look at this like one of the cases she worked on back when she was still Deputy Sheriff.

In every investigation, you had to look at means, motive, and opportunity. Means and opportunity were simple in this case. Senator Wen's group wanted the best minds in Eureka to live in a virtual environment so they could steal their ideas and technology. They kidnapped everyone on that spaceship and hid them away. The primary motive was to keep the crew from suspecting what was going on.

But how?

You can't exactly program real people to prevent them from suspecting something. You have to manipulate them into believing.

The first step, Jo assumed, was telling the crew that they'd been lost for four years. It would've kept everyone from being suspicious of any small and major changes. Four years was long enough to develop new technology. Four years was long enough for jobs or even buildings to change. Four years was long enough to fall in or even out of love. Four years was long enough for the people left behind to grieve. Theoretically, anyway.

That four year gap couldn't account for everything, though. Jo assumed those non-player characters were responsible for keeping everyone else in line and preventing them from becoming suspicious.

"It all comes down to motivation," Jo said, talking it through aloud. "What was the motivation of those NPCs?"

"Jo, they weren't real."

"Yeah, but you said they felt real. What were they programmed to do? Specifically."

"Keep us from figuring out that we were trapped in a fake Eureka."

At that, Fargo's face fell and she knew that he was thinking about Holly and how she lost her life by being the first to figure out what was going on. Jo placed her hand on his in sympathy.

"I'm sorry, Fargo."

"She was too smart for her own good," he said, with a bittersweet smile.

Jo wished that there was something she could do to make things better for him. Fargo and Holly had been good for each other. Holly's loss made her problems seem a lot less difficult in comparison. She'd much rather have Zane be alive and pissed with her and Carter than the alternative.

"I wish we could have saved her."

Fargo nodded and slipped his hand out from under hers. "Me too."

They both sat there in silence, mourning the loss of one of their own, until Fargo cleared his throat.

"They were programmed to keep us from questioning things," he said. "To come up with a reason anytime something happened out of the ordinary."

"And to keep people away from the NPC versions of anyone they used to be close to?" Jo asked. "Even with four years difference, I would have noticed if Zane was acting weird. The same way Carter would have noticed if Allison was acting weird."

Putting the virtual versions of her and Jack together would have been the best way to push Allison and Zane away.

"Maybe," Fargo agreed, "but what about Grace and Henry? The virtual Eureka didn't break them up."

"True." Jo tried to think of why her theory wouldn't apply to them. She came up empty. "I don't know. I just know there's something off about the algorithm and I need you to help me prove it."

An expression of concern crossed Fargo's face.

"Jo, the results might not change. The original GD imprint involved a brain scan. It wasn't that different from the information that it gathered from the crew's brains to make fake Eureka seem real."

"When was the original personality imprint taken?"

Jo knew that she had to be right. There might be some far-flung version of reality where she and Jack Carter ended up together, but it couldn't be a statistical near-certainty like Zane claimed it was. She knew how she felt about him and she knew how she felt about Carter and it didn't make sense.

Carter was her best friend. And sure, he was attractive, but that didn't mean she'd ever had any plans to hop into bed with him.

Fargo looked down at his computer. "The week before you started at GD."

A smile spread across Jo's face.

"I was right."

"Right about what, Jo?"

"Don't you see? That scan was taken of the other Jo Lupo, the one I replaced when we returned from 1947. That imprint was of a Jo Lupo who wasn't in love with Zane Donovan!"

She knew it. There was no way in hell the probability was eighty seven percent.

"The profile isn't static Jo," Fargo said gently. "It continued building after we got here from 1947."

Jo waved that away.

"That's stuff like actions we took at work and food we ordered, though, right? Nothing about who we are at our core."

The GD imprint from that other Jo Lupo didn't factor in what was in her heart and none of the updates would have registered that change.

"It might still show a probability of you getting together with Sheriff Carter under the circumstances that were presented."

"It might," Jo admitted. Carter was a great guy and there might have been a few lonely moments where she could see what would make him an appealing romantic partner. She had to allow for that possibility. She just didn't think it was as high a likelihood as Zane believed.

Jo needed Zane to believe that she wouldn't leave him. For his own sake as much as hers.

Their relationship had resumed almost without losing a beat, but great sex couldn't make up for the fact that he kept acting like their relationship was ephemeral and she had one foot out the door.

Zane, as long as she'd known him, had discounted the idea of faith in favor of cold, hard facts. So if he couldn't believe her promises that Sheriff Carter wasn't a threat to their relationship, she would prove it to him. With data, statistics, and the help of Douglas Fargo.

Jo Lupo had a plan.

"I need you to do a brain scan on me, Fargo. Get a new imprint profile. Then I need you to adjust the algorithm to use the correct profile for me."

She wondered for a second if she should get a new imprint for Carter too, but then decided it didn't matter. Regardless of what his profile said, hers would be a determining factor in any relationship probability.

"That's easy enough."

"I also need you to adjust the algorithm. Remove any of the programming that might have been in place to distance mine and Jack's NPCs from Allison and Zane. There had to be something in the code for those NPCs to push them away so they wouldn't suspect anything."

"Jo, this might not give you the answer you want. Maybe you should just go talk to Zane."

Jo dismissed the idea out of hand. If talking to Zane could have fixed this, she wouldn't have had to deal with weeks-worth of weighted looks and snarky comments. Zane's insecurity was unlike him and starting to grate on her nerves.

"I tried talking to Zane. He assured me that everything's fine when clearly it isn't."

Sure, there was something sexy about his whole you're mine attitude at first, but it was messing with the group dynamic. And the truth was, even though she still wasn't sure if she was meant to be in Eureka long term, she wanted to feel comfortable with Zane again and she wanted him to feel comfortable with her. She wasn't sure about Eureka or her job, but she didn't want to lose him.

"One other thing," she added, "this algorithm…it was primarily based on input from the crew member's brains, right? Your experiences, perceptions of reality…and maybe even your worries and concerns? Right?"

Fargo's eyes lit up as he caught onto her train of thought.

"You think the program used Zane and Dr. Blake's fears of losing you and Sheriff Carter to its advantage."

"You target your enemy's weaknesses," Jo said simply, thinking back to lessons she learned in her Special Forces days. "Can you rewrite the algorithm and run it again after we do a new brain scan?"

Fargo looked at the pages of code on the computer screen in front of him and then looked back at her.

"It's a lot of code and a lot of data. It'll probably take a few days."

Jo had promised Zane she wasn't going anywhere. Waiting a few days wouldn't be a problem.