AU set 5 months after the end of Season 3. Walter still couldn't believe he was in a relationship with the woman he loved. It hadn't been perfect, and he'd been far from perfect, but he was happier than he'd ever been in his life.

Author's note: This is canon up to the end of Season 3. Then it's all alternate universe.

Well, I'm doing it again, attempting to post 3 stories at once. I've been outlining this one since May, the day after the Season 3 finale as a matter of fact, and I wanted to start posting it before Season 4 begins. So once again, new chapters will be posted at irregular intervals, probably every other week or so, although I make no promises.

Disclaimer: This story is an amateur, not-for-profit publication produced solely for the enjoyment of other Scorpion fans and is not intended to infringe upon any rights of K/O Paper Products, Blackjack Productions, Perfect Storm Entertainment, SB Films, CBS Television Studios, or anyone else.

ARRHYTHMIA

CHAPTER ONE

ar•rhyth•mi•a, n, irregular heartbeat: an irregularity in the normal rhythm or force of the heartbeat

"One o'clock sounds good." Walter O'Brien stepped out of the bathroom, Paige's bathroom, to see her sitting on the bed and speaking to someone on her cell. She must have been interrupted while getting dressed, she was wearing just a pair of jeans and a bra. Suppressing the desire stirring inside him, he toweled off his hair as a short pause ensued before she added, "Okay, see you then." Ending the call, she tossed her phone onto the comforter.

"Was that Cabe?" He didn't know who else would be calling them so early in the morning. His question must have startled her because she jumped a little before turning around to look at him.

"No," she replied slowly, "no, just an old friend I used to work with. We're getting together for lunch this afternoon, unless Cabe does bring us a case."

Walter nodded as he found a pair of socks from one of the drawers which had been designated as his. They were practically living together. Most of his clothes and personal items had found their way into her closets and bathroom. He'd just used his own shampoo (and not just because Toby had teased him about using hers, making snide comments about how he smelled like a flower shop).

Nothing had been said. . .yet. And he was reluctant to bring it up. It was her apartment, he reasoned, plus there was Ralph's approval to be considered. He was willing to wait until both mother and son were ready to include him into their lives full-time. But until then, he was content with the status quo.

He still couldn't believe he was in a romantic relationship with the woman he loved. Five months, three weeks, and 2 days. . . It hadn't been perfect, and he'd been far from perfect, but he was happier than he'd ever been in his life.

The sex was amazing. He knew he'd reached that conclusion without testing his hypothesis. He didn't have any other experience to compare it to, he'd never been with anyone else. The first time had been slightly awkward, but even then it had been wonderful. And it continued to be wonderful. He sincerely hoped would never stop being wonderful. Paige was the woman he was going to love for the rest of his life.

"We don't have anything else on the books today," he declared as he snatched a pair of boxers from the dresser. "It'll be a good day to go out."

She glanced up at him with a smile which seemed strangely off. He thought he'd gotten pretty good at gauging most of her emotions by reading her expressions; anger, sadness, annoyance, disappointment, happiness, pleasure. . . This appeared to be none of those, yet he knew something was bothering her. He just hoped it wasn't him.

"Is everything okay?" he asked.

"Yeah." She got up off the bed and went over to the closet, taking a blouse from its hanger. She shrugged as she put it on. "It's just this friend. . . well, this friend and I didn't part on the best of terms and I've always felt kind of bad about it."

Letting out a breath of relief he hadn't screwed up again, he commented, "All the more reason why you should see her. Clearing the air is very important."

Paige grinned at him as she buttoned up her shirt. "Did you read that in one of your ladies' magazines?" she asked, and he heard the laughter in her voice.

"Maybe," he replied through tight lips as his face flushed with heat. He knew he shouldn't be so defensive about his choice of reading material, as he'd picked up several useful tips.

He was so caught up in his embarrassment, he didn't realize Paige had moved closer until she slid her arms around his neck. "It's okay, Walter," she murmured, entangling her fingers in his hair, grazing the back of his neck, and he shivered. "I think it's great." She lightly kissed his lips. "I love you." She kissed him again, this time more passionately.

"I-I love you, too, my-my little arrhythmia," he gasped out when they came up for air.

Out of all the silly pet names he'd tried out, that one was her favorite. His, too. Although more often than not, he called her 'love'. Because to him, she was tangible proof love existed. A low growl escaped his throat as he pulled her up against his towel clad body, taking advantage of her gasp to slip his tongue past her lips.

"Slow down, tiger," she said after playfully pushing him away. "We're already gonna be late. And I need to go check on Ralph."

"Okay." Reluctantly letting go, he watched as she left the bedroom in search of her son before dropping his towel and getting dressed.

ooooo

"I'm heading out now," Paige announced as she stood up from her chair, gathering her purse and sweater.

Walter glanced at his watch, noting it was twenty to one, before getting to his feet. "Have a good time with your friend," he said as she walked up to him. Leaning in to kiss her, he noticed the odd expression on her face again. Dismissing it as anxiety about seeing her old acquaintance again, he gave her a quick peck on the mouth.

"Okay, then, see you later. Love you."

"Love you too," he replied as she turned and headed toward the door. He smiled in what he hoped was a reassuring manner when she glanced back over her shoulder at him as she stepped outside.

"Ugh, you two make me sick," announced Happy, making a gagging sound before she returned to the miniature elevator she was constructing for her dollhouse.

"Hopefully not too sick for lunch," Toby said, suddenly appearing at her side. The behaviorist had been hyperactive all morning, practically bouncing off the walls. Literally too, as he'd repetitively tossed a blue rubber ball against the wall behind his desk for at least an hour. He'd also challenged Sylvester to a Rubik's cube contest (losing spectacularly), before volunteering himself to help Happy, who'd had enough when he'd broke off a piece of her dollhouse's roof in his eagerness to assist her.

"I was thinking about getting burgers from place we discovered last month," the shrink was now saying. "You know, when we went after that cyberstalker. Those were good burgers."

"It's on the other side of town," Sylvester pointed out. "The food will be cold by the time you get back."

"There are these marvelous inventions called microwaves," Toby said sarcastically as he walked into the kitchen. "And, oh, look. . . We have one right here." He waved his hands like a Price as Right model to indicate the appliance.

Walter rolled his eyes at the other man's antics before nodding. "Those were good burgers. I'll take a bacon cheeseburger."

"Me, too," said Happy. "With extra pickles and a chocolate shake."

The shrink looked expectantly at Sylvester. "I brought my own lunch today," the human calculator announced.

"Your loss." Toby turned to Walter. "Keys, boss."

"When are you going to replace your car?" said the genius as he tossed his keys to the psychiatrist.

"Why should I? You blew up Monte. Driving the company car is more than adequate compensation."

"I did not blow up your car. And it's not the company car. . . It's mine," Walter complained as Toby shut the door behind him. With a sigh, he walked back over to his desk.

"Hey, Walt, got a minute?" He hadn't realized Happy had left her workbench until she tapped him on the arm.

"Sure. What's up?" He detected a hint of worry in her tone, and it was also etched into her normally stoic face. She tipped her head to a far corner of the garage before heading in that direction.

The mechanic waited until he'd caught up with her before asking, "Have you noticed the doc acting squirrelier than usual lately?"

Walter frowned. Toby always acted like the class clown, poking and prodding and analyzing and generally getting on everyone's nerves. He was the shrink's favorite target, even more so now he and Paige were together. The sexual innuendo was almost nonstop. But other than that. . .

"I haven't really noticed," he said with a shrug.

"Yeah, well, you've been too busy getting busy with Paige to notice much of anything." Happy smirked at him.

Walter ignored her jibe. "He's just being his usual pain in the ass self." Sensing she had more than a casual interest in the behaviorist's behavior, he inquired, "Why do you ask?"

"I think he's been gambling again."

"I thought he promised not to."

"Are you really that naive, O'Brien? People break promises all the time." She let out an exasperated breath. "He's been acting very secretive lately, and his moods are swinging, like. . .well, a swing."

"His mother was bipolar, maybe Toby is. . ." He doubted the shrink suffered from the same disorder though. It surely would have manifested before now.

Happy shook her head. "He's never been like this before. He knows how I feel about his gambling."

"Your attitude is rather hypocritical. You make bets with Sly all the time," he pointed out, knowing he was probably exposing himself to her wrath.

"That's different. It's just for fun. And Sylvester's not threatening to break my kneecaps if I don't pay up."

Walter had to chuckle at the mental image of the younger man threatening Happy over anything.

"I'm so glad you think this is amusing, you jerk." Oh, crap, he'd really pissed her off now if her glowering stare and crossed arms were any indication. "The doc made a promise to me that I hold as sacred as our wedding vows."

"So what do you want me to do about?"

"Keep an eye on the moron, maybe see if you can get any info out of him. But be subtle about it."

"I'll do what I can." He could be discreet. . . Maybe. . .

"Be subtle," she repeated before stalking back to her work bench.

Walter covered the distance back to his desk, thinking with every step the mechanic was fretting over nothing.

ooooo

"Hey, everyone, gather round. Got a case!"

Walter glanced up from his computer screen as Cabe strolled into the garage a week later, followed by a woman. Hitting save, he got up from his chair and joined the rest of the team around the conference table where the older man was introducing his companion to the rest of the team.

"This is Gloria Svenson. She's in charge of the Turing Institute and. . ."

"The Turing Institute?" Walter turned to grin at Sylvester, the excitement on the human calculator's face matching his own.

"You've heard of it?" The agent seemed shocked.

"Of course," said Sly giddily. "They're doing groundbreaking work in the area of theoretical computer science. They can do things with algorithms that make what Walter and I do look like toddlers goofing around."

"Yeah, if the toddlers in question had IQ's of over 180," said Toby with what Walter was sure was sarcasm. His suspicion was confirmed when Happy smacked the back of the shrink's head and gave him a dirty look.

The woman smiled at the younger man. "Thank you for thinking so," she said, a touch of a Swedish accent in her voice.

"So what's the problem?" Walter asked, wondering why someone from one of the most advanced scientific research facilities in the world would need help from a group of misfits. Granted, some of the smartest misfits in the world, but still. . .

Cabe answered his question. "The institute is working on a highly classified assignment for the US government. Everything was going smoothly until a few weeks ago when elements of the algorithms being run for the project would randomly change."

"So they were hacked?" Again, Walter didn't understand why they were needed. He turned to look at the woman. "Surely you have in-house computer experts to track down the perpetrators?"

"We do," said Ms Svenson. "Either we weren't compromised or whomever did it was so good, they didn't leave a trace."

"That's impossible," he said. "No one's that good. Not even us. There's always some remnant left behind."

She shook her head. "Not that our highly skilled engineers could detect. So far, neither external nor internal sabotage has not been rule out. My colleagues don't agree with me, but I don't believe we've been hacked. And I don't think we've been internally infiltrated either." She flicked her eyes in the Homeland agent's direction before returning her gaze to Walter. "I understand you have encountered a quantum computer before."

Once again, he and Sly looked at each other, the other man practically salivating. "Uh, yeah. . . We, um, have," Walter replied, barely able to contain his own eagerness. "We. . ."

"I've read the report," she said. "It's amazing you all weren't killed." She shook her head and smiled, blinking in a way Walter thought something must be irritating her eyes. "But I digress."

"Is that why you need us?" Walter lifted his head sharply as Paige gave voice to the question he'd been about to ask. She was standing on the other end of the table, her arms folded firmly against her chest. And if the frown on her face was any indication, she wasn't too thrilled by this new assignment.

"Yes." The other woman's countenance sobered. "I think the quantum is changing the algorithms on its own. And I want you and your team, Mr O'Brien, to help me prove it."

"Ms Svenson," Walter said when his brain slowed down enough he was capable of speech. What she believed, what she was asking them to do. . . It was insanity. But not entirely impossible. "We're flatt. . ."

"You can call me Gloria," she said, her accent slightly stronger than before, showing him her straight white teeth. She had very sharp canines, he noted.

"Okay, Gloria." Walter knew the polite grin plastered to his face was probably more like an awkward grimace, but he couldn't help it. "It's Walter, by the way."

A choking sound came from the other side of the table, and he glanced up again at Paige. His grin dissipated in an instant. He'd obviously done something wrong, if her angry expression was anything to go by. He doubted it was because of the case, he hadn't even accepted it. . .yet.

But he couldn't let her emotions deter him from working on one of the most challenging and intriguing missions Scorpion had ever been offered. He just hoped whatever he'd done to upset her wasn't as insane and nearly impossible to fix.