Notes & Spoilers: Thanks to lilallisun, thelymachy and damalur for their help in figuring this one out. It only took a few months for me to do so. General knowledge of both seasons 1-2, as well as specific for 2.23: The Monopolar Expedition; AU for season 3.

May 15, 2009 – 2:14 pm

Four days after the boys left on their expedition, Penny got an invite from Skype to video conference with them. She could barely contain her excitement and fairly danced around the apartment until she realized that a faded tee-shirt and hip-hugger panties probably wasn't the best choice of attire. And once she decided to change, webcam or not, she wanted to look her best. A little over an hour later, she stood before her mirror and slipped the blue and dark pink Penny Blossom into her carefully arranged curls. Her make-up was perfect, her outfit -- a form-fitting tank-top, a dark pink to match the petals of her hair accessory, and tight-ish blue jean shorts that matched the bud -- looked fabulous. Butterflies fluttered wildly through her stomach as she sat down before her laptop.

The first few days after they had left, Penny had found herself pining for Leonard. She'd recall the way he would look adoringly at her, or how he always found an excuse to help her, be near her. How smart and how funny he could be. What a nice, sweet guy he was. She berated herself constantly for not saying something because she knew that based on their last conversation, he very well might have stayed behind leaving Sheldon and the others to their scientific investigations.

*Sheldon*

Quickly, her mind shied away from the thought of him. It had been some crazy, mental hiccup; an aberration was the technical term. She'd actually done the research and oddly found comfort in the science of it. Aberration: A disorder or abnormal alteration in one's mental state. Yup, that's what it was; that was all it was. Her subconscious had confused Stuart and Leonard and mixed them up in the form of one Sheldon Cooper. In his presence, it had been easy enough to remember the lunacy that surely involved that aberration, but with him gone ... Well, it was just better not to think about him at all.

"Hey, Penny!" Leonard called out and Penny quickly brought her attention to her laptop screen to see his bespectacled, grinning face. She smiled in anticipation of the rush that would come from seeing Leonard for the first time in four days!!

She waited.

It was coming.

Any minute now.

"Oh, beauteous lady!" cried Howard who crowded next to Leonard. "What a sight for sore eyes." His gaze dropped to her cleavage with little finesse and he added, "a bountiful sight." And with that, any chance at a rush of joyous emotion evaporated. Fair or not, seeing Howard Wolowitz's leer made it perfectly clear that she had not missed him one teeny bit. Not yet anyway.

Crowding Leonard on the other side came Raj's pearly whites, and despite the fact that when you boiled it down, Penny really didn't know him much at all, she couldn't help but smile because of what she did know of him – from their mostly silent communication along with his interaction with the others – he was a sweet guy. And he did have a *fantastic* smile. He thrust a thumbs-up in front of Leonard's face and Penny couldn't help but giggle.

"Raj," Leonard whined. "Give me a minute to say hi." An uncomfortable knot formed in Penny's stomach. In her delirium over the last few days, she'd not only highlighted all of Leonard's positive qualities, she's also completely ignored his negative ones. Like the whining. Adjusting his glasses, he pushed Raj and Howard out of the frame and winced towards Penny. Moments later, she realized it was a smile and she smiled back.

Even with Howard gone, that joyous rush still remained mysteriously absent. The butterflies stopped fluttering and were at a standstill. "I – I mean, we – we, all of us, miss you." Penny weakly smiled. Yup, this was the Leonard she'd conveniently forgotten about. The one who would never man up and simply tell her how he honestly felt. No 'I miss you,' but a cop-out of 'We miss you.'

"Oh, Leonard," Penny sighed and he brightened visibly, unaware that the response wasn't one of mutual feeling, but rather that Leonard was just being so very … Leonard. Unable to let him down, though, she added the words he obviously expected. "I miss you guys, too." His smile dimmed a bit when she made the statement plural, but, damnit, if he couldn't say it, why the hell should she? He was the one who'd had a crush on her for two years now.

There came a shuffling noise and scathing voice from off-camera and Leonard glanced over his shoulder. "Honestly, Wolowitz, not even five seconds and you're leering."

The butterflies began fluttering. Penny froze and firmly ignored their flight, smiling brightly at Leonard – too brightly, but he wouldn't notice. "So, how are things?" She asked quickly. Leonard smiled back and opened his mouth to speak.

And then *he* came into view, smoothly pushing Leonard out of the way. The butterflies began beating wings so frantically that she was sure somewhere on the other side of the world – possibly where the boys were – a snowstorm was beginning to furiously form. In the back of her mind, Penny knew that her knowledge of the Chaos Theory a.k.a. the stupid Butterfly Effect came from Sheldon's presence in her life, and not that Ashton Kutcher movie. Oh, and speaking of the good doctor …

"Penny, hello." He stood straight, his hand folded neatly behind his back. "Things, as you so generically put it, are going quite well. We've established base – and," he paused, a frown crossing his features. "What's wrong with your face?"

Without thought, Penny's hands rose to touch her cheeks. "What's wrong with my face?" She parroted back to him.

Sheldon shook his head, "nothing now. You just had a peculiar smile on it. It appeared to be, as they say, plastered on. Too bright. It wasn't –" and again he paused, his voice faltering slightly as if aware that he was revealing something, but the confusion shading his speech showed that he had no idea what exactly he was revealing. "It wasn't you."

And there went the butterflies, madly, wildly fluttering, flitting, zooming at warp-speed inside her stomach. Penny blinked and allowed the possibility for the first time since she had called out Sheldon Cooper's name in the throes of passion while making-out in the backseat Stuart. It might not have been a crazy, mental hiccup after all.

May 16, 2009 – 11:37 am

All thoughts of Sheldon and butterflies had been resolutely put from her mind, and she was tunelessly humming the latest pop hit while grocery-shopping. Suddenly, she looked up from the oranges, and right before her was Stuart. Comic-book, two dates that ended disastrously both times because of Sheldon, Stuart. Of course. There was a moment (or two ... or ten) of awkwardness, but they both gamely smiled and exchanged pleasantries. "So I guess Leonard was pretty mad," Stuart said after they'd both agreed, that yes, the weather had been particularly nice the last few days.

Cocking her head to the side in confusion, Penny shook her head before replying. "What do you mean? Why would Leonard be mad? He's with ..." she paused and then, not able to even say Sheldon's name because saying Sheldon's name meant that she had to think about those damn butterflies and his relation to them and she was simply not going there. "He's with the guys."

"Yeah, I know I heard about that," Stuart laughed dryly. "Sheldon stopped by and pre-ordered a bunch of comics." It was the Mexican she'd eaten earlier, Penny was convinced, as she began rubbing her stomach at the mention of his name. "I was thinking that Leonard wasn't too happy with me after what I told him."

Penny shook her head, the butterflies -- Mexican food! -- momentarily forgotten. "What did you tell him that would make him mad? This is Leonard; it takes a lot to upset him."

"He didn't tell you? Oh, well, that's surprising." Rolling his eyes, he sighed. "In for a penny," he grinned. "In for a pound, I suppose. After our last date," he raised an eyebrow and gave a sardonic smile. "Raj and Howard dropped by the comic store and let it slip that Leonard had a crush on you and had been feeding me very, very bad tips on how to proceed with you."

"He what?!"

"Uh, yeah. That was rather my reaction. So when he stopped by to apologize, "Stuart used air quotes, rolling his eyes again, "I decided to burst his bubble a bit. I was going to tell him about your little crush on Sheldon, but --"

" -- I do not have a crush on Sheldon!" Penny bit out between clenched teeth, her voice rising just a tad. Taking a breath, she offered a brief smile at the shoppers looking in their direction. Taking another calming breath, she continued more quietly. "It was an aberration. I looked it up; that's all it was. An a-ber-ration." She relaxed her shoulders, and unclenched her teeth again before continuing. "I told you that." In the absence of Sheldon, Penny was once more whole-heartedly clinging to that belief. Anything else was just crazy.

"Fine," Stuart laughed. "The point is I was going to tell Leonard about the, uh, aberration, but realized that he wouldn't believe me and what fun would that be? So I told him you said his name instead. I figured he would have gone rushing to sweep you in his arms, and make a fool of himself." Stuart's voice turned bitter, "like he did with me." Seeing Penny's expression, he took a step back. "Yeah, definitely should have kept quiet. Look, Penny, I'm sorry, but I was upset with Leonard ... and with you." He spread his hands out. "Leonard obviously didn't say anything and if he doesn't know about your Sheldon 'aberration,' then Sheldon doesn't either, so it's all good. Right?"

Sighing, Penny glared at him for a moment and then relented because it was pretty shitty of her to call out another guy's name -- even if it meant absolutely nothing! -- while making out with him. She nodded. "Yeah, it's all good."

May 16, 2009 – 2:45 pm

Penny clicked the little red telephone button on her cell phone with a little more vehemence than usual. And sighed. And once more repeated the definition of aberration to herself. Lauren had no clue. Three hours of spilling out the situation to her sister and her sister's best friend back home had only made her tenser about the whole thing. Because of -- and here Lauren had paused not quite sure how to label Sheldon based on what Penny had told her, before settling on -- how odd Sheldon was, and how asexual she thought him to be, she believed that Penny had transferred any romantic feelings she felt towards him to Stuart.

"Stupid therapists without a clue." Penny muttered under her breath, "think they know everything. Oh, I have a degree, I'm smarter than you. I have two PhDs. I'm special!" Groaning, she threw a cushion across the room. "Stupid Sheldon!"

Standing up, she stomped towards her bedroom and began grabbing dirty laundry, grumbling to herself. Pausing, she looked at the contents without seeing anything and burst out: "I do NOT have feelings for Sheldon!" She held the angry stance for a moment before slumping onto her bed, letting the basket fall to the ground. Lying back, she thought about what Lauren had said. How once things with Stuart had fallen apart, she'd then transferred those feelings to Leonard, because firstly, she'd had a previous romantic relationship with him, failed or not. Secondly, again with Sheldon's oddness and apparent asexuality, it simply made more sense to Penny that saying Sheldon's name in the throes of passion had been because she had sublimated her feelings for *Leonard* because he made more sense as a viable romantic partner.

Two years ago, this long-winded explanation, filled with three and four syllable words would have left her bewildered and frustrated. Now she simply accepted them as a matter of course because so many conversations in her life now contained information so over her head that she was used to it and pretty much got the gist of it. Once Lauren had finished, Penny was ready to combat her diagnosis with her own research. "Okaaay. Yeah, I don't think so. Like I said, I really think that it was just an aberration." There had been silence on the other end. "I looked it up. It's logical."

Silence.

"Yeah?" Penny pushed.

She'd then heard a long-suffering sigh from the other end of the line. 'Well, maybe you're right, Penny. You know your own feelings and these guys much better than I do." Lauren's voice had dropped slightly and she added nearly sotto voce, but just nearly enough that Penny could most definitely hear her. "I only get paid to dispense this kind of advice for a living." And it was at that point that Penny had realized she needed to end the conversation.

"Look, I do appreciate you listening about this, I just -- you said it: You don't know Sheldon, so if you did, you'd understand why I just have to be right about this."

And then it had been Lauren's turn to brush her off. "Okay, Penny, if you're sure. Just keep in mind what I said the next time you talk to Sheldon. If you at least open your mind to the possibility, you might be surprised. After all, Penny, you did talk about the guy for an hour straight."

"I talked about Sheldon, Leonard and Stuart!"

"Yes, you talked about the other two, but I have only the vaguest impression of them, other than Leonard's long-standing crush on you. But this Sheldon? With the way you've gone on and on about him, I could write a chapter on him alone in the book I'm not presently writing but may if my client list remains so short."

Penny rolled her eyes in memory. Lauren just didn't get it; she couldn't. Sheldon wasn't like anyone else and so in order to even get an inkling of what he was like, you had to explain him, you had to spend "an hour straight" explaining him. Lauren couldn't see that, even if she did concede the possibility that Penny was right at the end she still had to give one more push of her own. "You may be right, but, I urge you to keep your mind open to the idea that there could be something to what I said."

Closing her eyes, Penny threw an arm over her head. She was sure, absolutely sure that she was right and Lauren had no idea.

May 16, 2009 – 6:33 pm

Her laundry was done, but her thoughts were still whirling when she got another invitation to Skype. Warily, she agreed. She wasn't happy with the information given to her by Stuart, but she'd just deal with Leonard if he ever got the guts to bring it up. (Likely not, she figured.) And Stuart was right; the most important thing remained between them: the aberration. Neither Leonard, nor Sheldon knew about that. And that is how it would remain. Despite what Lauren had said, Penny was still convinced that she was right and that calling what had happened anything other than an aberration was just crazy.

"Hello, Penny." It wasn't Leonard speaking.

Penny found herself rushing to sit in front of the screen of her laptop, her stomach all aflutter. It was Sheldon, this time he was sitting down, instead of standing at attention like a Starfleet officer -- her eyes widened and she looked away a moment, shaking her head quickly. Man, she spent way too much time with her boys. "Penny, are you alright?" Sheldon's voice brought her back.

Turning to look at him, her eyes traveled over his face and chest where she could see the top of the Flash logo. "I'm fine. I just -- where's everyone, Sheldon?" He didn't answer right away, instead he stared at her searchingly for a moment before glancing quickly down at his shirt. "Sheldon?" she repeated and he gazed back up at her and blinked before speaking.

"They are setting up helium mixture gas proportional counters to produce large signals for the slow-moving monopoles. We've decided to use the atomic induction mechanism proposed by Drell." His eyes lit up as began to explain what exactly this Drell had proposed, but she'd stopped listening and he finally shut up when no doubt noticing the glazed look that had clouded her gaze. With a roll of his eyes and a peeved sigh, he skipped the scientific mumbo-jumbo. "They are presently outside, while I am alone in here which makes this ideal as I -- well, I wanted to speak with you." He paused, licking his lips. "Privately." And she could have sworn his eyes dipped to her lips before jumping back up to meet her gaze. And just like that, when she met the blue, the butterflies went into warp speed and she knew, with that one word, that one stolen glance, that one look ... she knew that it wasn't the Mexican food. And with that acceptance came a peace that had been stolen a few weeks ago in the back of Stuart's car.

Shaking her head, she couldn't help the gentle smile that crossed her face. "Lauren was right," she murmured to herself. Despite all of her grousing and denials, suddenly -- in the very face of it -- Penny was fine with it; she couldn't be upset when she was looking right at him. At the moment, even his comical look of confusion was endearing. "I miss you, Sheldon," she said softly.

The confusion faded away as a slight blush lit his face. Ducking his head, he nodded jerkily. "I miss you as well, Penny. This, I admit, has come as a surprise." He paused and met her gaze, a boldness now meshed with the shy. " I must say that I also find it surprising to hear the same from you."

Thinking over the last few days of confused mental torment, Penny let out a dry laugh, "yeah, the feeling's mutual."

Sheldon opened his mouth to respond, then stopped with a perturbed look on his face. "Seeing you the other day reminded me of home." Her smile bloomed and Sheldon inhaled sharply. He straightened his shoulders, as if getting a firm grasp on himself and the softness of his gaze melted away before he narrowed his eyes. Giving a quick shake of his head, he began speaking rapidly. "Speaking of ... have you been airing out the apartment? Getting and sorting the mail, and making sure there are no expired items in the refrigerator or cabinets per my itemized lists?"

Sitting up straighter, Penny's eyes widened and although she noticed his eyes dropping away from her face quickly before rebounding back with an even narrower squint, she was suddenly too exasperated to wonder about it. Maybe it was because of her frustration with all of her own confusion the last couple of days, or it could be because he had just ruined the moment. Then again, perhaps it was because he was thousands of miles and three months away that any strike didn't matter. Possibly it was because she missed their sparring. Or maybe, just maybe, it was because he was simply Sheldon and he drove her insane and thus deserved some payback. Of course, she smiled as she slumped back against the couch, it could just be that it was so very them. Her grin turned evil. "Nope." She drew out the 'o' and popped the 'p.'

"Well, I hope tha -- what?!" He sputtered; he actually sputtered. "Penny, I left very detailed and specific instructions."

"I know," she responded simply, and her smile softened to sweet. She even widened her eyes innocently and threw in a little head tilt. This time she did note how he cocked his head slightly to match her own and his gaze wandered over the curve of her neck before straightening up again with a start, his posture rigid.

"Well, then why?" That high-pitched squeak that sometimes became his voice when he was emotional took over. "I mean –" and there he went sputtering again. "Penny! What reason could you possibly have for not doing the incredibly simple tasks that I require of you?"

Looking away from the monitor, her jaw dropped a tad and she muttered to herself, "Did he actually say what I just heard him say?" Turning back to face him, she clucked her tongue and pursed her lips. "Of course he did," she answered herself.

"Did what?! Who? Are you talking about me? Penny, is someone else there?" He was past sputtering, and now his voice sounded strangled in exasperation. And a beat of red flushed his face. "If you are playing games at my expense, well, I --" Penny's grin softened into a sweet smile. Poor baby, she thought. He's about to have a fit.

"Sheldon, I'm alone. I wouldn't tease you like this with anyone around." The blush faded and he took a breath.

"Well, I should think not." She could tell he was straightening his Flash tee-shirt just out of view of the camera. When all was well, he spoke again, his tone not happy. "Now, back to the matter at hand. Again, I ask: What reason could you possibly have for not doing what I require of you?" His gaze was imperious, eyes wide and demanding and Penny couldn't help it. She laughed, filled with a crazy joy. This was the man she'd fallen for? Seriously, this guy? What I require of you, my ass!, she thought, but it was filled with affection. And for the first time, it hit her that -- although thinly veiled and surely Sheldon had no idea -- there had been a touch of flirting in their fighting all along. Shaking her head, Penny ignored his pointed glare and thought of their first meeting in his apartment. His white board, his tentative smile as he showed off his science genius and she couldn't understand for the life of her that she -- the social queen -- hadn't realized it from the first. The butterflies may have been quiet due to his, well Sheldon-ness, but they'd so been lying in wait and one sweaty night in the back of Stuart's car had unleashed them somehow. Like Lauren said, the combination of Stuart's similarities to Sheldon, and what she thought were "sublimated feelings" for Leonard. When it had been Sheldon all along.

"Penny? Penny?! PENNY?!" Jerking up, she met his now infuriated gaze. Penny couldn't help but continue to smile fondly at the tall, lanky jerk and she noticed for the first time how big and beautiful his eyes were. "I'm beginning to seriously re-assess any warm regard in consideration of our distance at this moment, Penny," he bit out stiffly.

Laughing, she relaxed again and rolled her eyes. "Sheldon, I checked your refrigerator and cabinets, got your mail, sorted it and wrapped it with rubber bands to keep the days separated. And, yes, I aired out the apartment. All per your list. Happy?"

"No," he sniffed, "Although, I'm no longer unhappy. I just don't understand why you simply didn't say so in the first place instead of lying to me and unnecessarily riling my emotions."

"Maybe it's because you were being an ass," she offered with a bright smile and felt an almost misty joy at the thought that she truly did miss him; God help her, she was crazy about him. Dr. Sheldon Cooper, OCD-insane, beautiful mind-genius, nit-picker-extraordinaire. Go figure. She sighed happily and caught just the teeniest bit of a smirk from him before he quickly schooled his expression.

"I -- I do not know how to respond other than to express my complete and utter disagreement with your statement. I was merely -- "

" -- okay, fine. So," she dragged out the word. "Whatcha doing, Moonpie?" She stretched tightly and took a deep breath, her chest rising and falling with the action. As she settled back into place, she noticed that his gaze had dropped again, but this time … hmm. Curiouser and curiouser. A most unexpected thing. Sheldon's eyes were glued to her breasts. Yes, Sheldon as in Dr. Sheldon 'I'm-not-afflicted-with-sexual-appetites' Cooper was staring at her chest. Hmm. Testing her theory, she stretched again, making sure to really exaggerate the motion. His eyes widened slightly and he licked his lips. A grin lit her face. "Sheldon?" She called out coyly, a sing-song quality in her voice.

His gaze jerked up as if he'd been stung and his face turned beet red. "I have to go. Goodbye, Penny." He reached to shut their connection down, and then stopped, his entire frame freezing. He looked past her head, avoiding her eyes and spoke, his tone stilted. "Do continue to follow my itemized lists." He inhaled sharply and then his shoulders slumped and he sighed resignedly before continued in a softer voice. "Please." There was another long pause and then his gaze, soft once more, finally met hers again. "On further thought, my warm regard remains intact. Goodbye, Penny."

His image flickered and disappeared. Penny pressed a hand lightly to her stomach, and let out a tremulous breath. It didn't stop the butterflies from playing tag.

October 16, 2009 – 8:22 pm

The sun had set and the only light in the room was filtered pink through the nearly transparent scarf that Penny had placed over her bedroom lamp. It cast a soft blush over Sheldon's back, making the freckles here and there barely visible. Leaning close, Penny kissed first one and then another before pulling back quickly, knowing that he'd turn to face her in the next second or two demanding to know what she was doing and why. And then he would grab the 'Protocols for a Romantic Relationship" journal he kept by the bed and add notes, thus diminishing any chance of "coitus." Like clockwork, he rolled over just as she was finishing her thought, already speaking, "Penny, why--"

She cut him off before he could even get started. "-- Sheldon, show me the Butterfly Effect." Lying back, she pushed the sheet down, baring her breasts. He was quiet for a moment, his gaze moving over the reveal of her naked body before he looked away and gave himself a little shake before speaking.

"The Butterfly Effect, as you call it, is derived from Chaos Theory. Chaos Theory is a branch of mathematics which studies the behavior of certain dynamical systems that may be highly sensitive to initial conditions. That sensitivity is what is known as "the Butterfly Effect." As a result of this sensitivity, which manifests itself as an exponential growth of error, the behavior of chaotic systems appears to be random. That is, tiny differences in the starting state of the system can lead to enormous differences in the final state of the system even over fairly small timescales. This is sometimes presented as esoteric behavior, but can be exhibited by very simple systems: for example your butterfly effect." Sitting up, Sheldon paused and began expounding on the theme. Penny sighed, his words a white noise to her own thoughts and she tried to figure out how to get him doing – and not saying – what she wanted.

"The term "butterfly effect" itself is related to the work of Edward Lorenz …" Blah, blah, he continued on while Penny continued thinking, idly running her finger up and down his arm, but he was so immersed in his topic, he didn't even notice. "… the more poetic 'butterfly.' I, myself, don't see the difference: Seagull, butterfly, they both have wings, thus either would suffice for the analogy."

Penny rolled her eyes and realized that the time for subtlety had passed; she was going for his Kryptonite. With her eyes locked on his face, she purposefully shifted, sending her breasts bouncing in a fashion sure to capture his attention. Immediately, Sheldon stopped speaking, his eyes drawn back to her nude form. He swallowed and then continued, but now his voice was huskier. "Why you're asking about this, I have no idea. I've explained the theory to you several times and despite your far less inferior intelligence when compared to my own, I do find it rather difficult to believe that you've yet to grasp this fairly simple concept."

"Sheldon," his eyes finally met her own. "I didn't ask you to explain it to me, I asked you to show me." And she smiled, a slight curve of her lips, and then added another shimmy of her body to get the point fully across. His eyes widened, his mouth began to form a quiet 'oh!' and then he smiled back. Reaching for the sheet, he flung it off of her body completely and maneuvered until he was lying nearly across her, but not quite. Bending down, he sighed ever so softly against the curve of her neck.

"One could easily grasp the concept of the Butterfly Effect were it reduced to a smaller scale," as he spoke, his breath ghosted against her skin and every word or so, the lightest flick of his tongue brushed against her throat. "For instance, if I were to place one finger here …" He continued, while putting his words into action. On the other side of her neck, just behind her ear, he placed one long, beautifully slender finger and stroked her skin, before crooking it ever so slightly to allow the gentlest scrape of his fingernail in a back and forth motion. "Because this is a particular erogenous zone of yours," he whispered into her other ear, "that simple, unrelated action would cause your toes to curl." His feet entangled with hers, finding the proof of his words. "Your breath to hitch, your heartbeat to speed up," and one hand moved lazily up her hipbone, tenderly dancing over her stomach before cupping her left breast and counting the number of beats per second quietly to her. And then softly, deeply, "do you understand the Butterfly Effect now?"

She gasped and arched her body, then angled towards him, her arm wrapping around his shoulders. Pressing her mouth to his, her lips parted and without words, she showed him once again that, yes, she understood. She definitely understood.

THE END