Author's Note: I've been staying up watching TBBT and reading Shenny fanfics and watching videos so...this little thing was spawned from the above endless events. One shot story, read below. I suppose this takes place at the end of the last finale, I don't know. Sorry of this bites, I haven't had proper practice roleplaying TBBT, let alone writing any fanfiction myself, but I tried.

Title: The Time Paradox Hypothesis

Summary: Three conversations Penny and Sheldon shared about time travel, and one they did not.

Pairing: Sheldon and Penny

Time frame: Supposedly after season 5 or whenever.

The Time Paradox Hypothesis

The first time Sheldon and Penny discuss time travel is when Penny is in bed. Leonard is staying at work and Penny has the flu. The only person who might bring comfort or at the least be the awkward company to whine to, was Doctor Sheldon Cooper. If he had been summoned a year or two ago, he would have promptly declined but now that he and the blond waitress were friends, he understood it was his obligation to do so-called favors for people. And she had taken care of him after all when he was under the weather. Another point being, his Meemaw and Mother would insist he be a gentleman and stay by an ailing lady's side. So that was why he was sitting by Penny's beside at ten o'clock at night when Penny turned her head toward him and let out a terrible phlegm filled cough. Gingerly handing her a tissue, Sheldon's expression was quite unamused and unsympathetic. "You do realize that if I had work in the morning, I would not be here." He insisted to Penny who weakly took the offered assistance.

"You know if it would bother you much, just invite a time machine and stop me from getting sick." Penny said, her nose quite stuffy and her logic rather ill-conceived but even more so thanks to her illness. Sheldon lets out his now trademark chuckle of sorts and spares the sick girl a long lecture on how poor her proposal was.

"If only it were as simple as your community college brain imagines." Sheldon said dreamily and sighed as Penny blew her nose and groaned. "Sometimes I envy the simple minded but thank goodness I'm not like one of you." Sheldon recoils his musings as he sees Penny's cup of soda is near empty. The genius hops up and goes into the kitchen to refill it, but when he once again passes into her kitchen area, the boy cannot help but shake his head at the typical mess. After returning to her side, he hands her the glass and remarks, "If I did have a time machine, I would be rather tempted to go back and show your past self how habits of cleanliness developed early on can really shape one's adult life. I mean imagine if you were better organized, my, you could be a wonderful actress who doesn't have to serve overweight people cheesecake that is horribly overpriced, even for the state of California."

Penny is far too congested and annoyed to say anything so she just grabs her drink and throws it on Sheldon. Of course she doesn't realize immediately that he might have been trying to help her or hypothetically do so. Or perhaps it was his un-charming way of making a joke at her expense and the customers who frequented The Cheesecake Factory. Either way, Sheldon doesn't know what he did wrong so he chopped her action up to delirium and just grabbed a cloth to clean himself up. The night passes with Penny staying silent and Sheldon toying with the idea of him someday being able to go back and forth in time. It's an idea that distracts him from even trying to decipher Penny's odd silence, save for the coughs and groans. And when Leonard comes over to relive Sheldon of his duty, all Penny can do his smile and say, "Thanks Sheldon. Maybe if I can go back in time I would have asked you to sing Soft Kitty to me rather than talk about my messy habits."

"Well it's too late now." And with that Sheldon just goes back to his apartment to take a long well deserved shower.

The second time Penny and Sheldon talk about time travel, is when they're standing in line at the movies. She, Sheldon, Howard, Bernadette, Amy, Raj and of course Leonard were waiting to see the new Prometheus film. Amy and Bernadette are talking about the actors and actresses in it while Raj and Howard are discussing the director and the idea of the movie being or not being a prequel to Alien. This left Leonard, Penny and Sheldon to converse but at the moment Leonard was on the phone with his mother who had picked quite an inopportune time to call so he had to step out of line to deal with her. Penny turned to Sheldon who was sitting in a well placed lawn chair. "So if you had a time machine, I'm guessing you would want to have gotten here earlier?" Penny questioned him.

Sheldon sighed, giving the blond a bit of an exhausted expression, he wasn't sure if she was using sarcasm or not but he just looked ahead of them at the people and then turned his head to eye the people behind them. "While this isn't a preferred placement in line, and while I would have hoped for better after the Indiana Jones incident, it wouldn't be a viable instance where I would use a time machine, honestly Penny, do you ever think?" He huffed a bit. Penny just stood there, staring at the genius on his low level throne. Folding her arms, she shrugged. "One uses a time machine for important instances, not for something this trivial." Sheldon continued.

"I'd go back in time to stop myself from asking that question." Penny mutters and this time Sheldon does catch a whiff of an emotion he had been trying to figure out. He had upset her. Had he been condescending? He had just questioned her honest thought behind her proposition.

"I'm sorry Penny." Sheldon expressed and she just glanced off. The situation wouldn't be remedied so quickly. It bothered Sheldon that he had upset the girl and knew everyone else would only bother him more when they found out that Penny had been offended for about the two thousandth time. Standing up, he gestures that she sit down in his chair. "You can have my spot." He says but then raises a hand, "Only until we have to move in line." He adds as Penny slowly unfolds her arms and weighs the significance of the gesture. The girls ends up sitting down while Sheldon stands in her place. The others soon notice the change and Sheldon just says that it had to be done, not wanting to further ruffle Penny's feathers. The rest of the night went by smoothly but this time it left Penny wondering how a time machine could really change her life.

The third time the two mention time travel, is after Leonard and Penny break up. Leonard and Penny had been dating for over a year, Leonard kept mentioning settling down and having children and once again it made Penny very uneasy. The two of them ended up having their worst fight which resulted in many harsh things being said. And in the Penny wound up packing boxes at three in the morning. It was at the time that the three knocks, followed by her name, broke Penny's sob crying. This pattern was repeated twice more before Penny trudged over to the door and opened it. Sheldon was standing on the other side looking very concerned which was very un-Sheldon-like. Her watery eyes could barely make out the guy but she could tell from the blurred tallness, that it was Sheldon and not Leonard. Somehow her brain hadn't bothered to acknowledge the signature knocking. "What is it Sheldon? Can't you see I'm packing?" She wailed and just dragged herself back to her couch and sat down next to a half filled box of ruffled clothes and magazines.

"It's three o'clock in the morning. Who on earth packs at thee o'clock in the morning?"

"Someone who doesn't belong here." Penny just sniffled and grabbed a shirt from her box and blew her nose in it and put it back in the box which caused Sheldon to flinch and reconsider coming over.

"Leonard mentioned you two broke up...again."

"And?"

"And I wanted to come by and see if you're alright." Sheldon answered simply.

"Well I'm not." Penny said and rubbed her eyes. Before she could grab for the used shirt, Sheldon throws the box of tissues into her lap that he had brought over. Penny then sees a bottle of vodka and a small pint of Rocky Road ice cream is also in Sheldon's possession. "You brought me ice cream and vodka?" And a small warmth fills her heart as she manages a weak smile at her friend who is clearly a bit out of sorts, unsure of how to proceed.

"I read that social norm dictates that once one has broken up, they must either drink or consume ice cream." Sheldon explained and made his way through the maze of her mess and grabbed a bowl and began to serve Penny some ice cream while she sat down, trying to calm herself. "I know you and Leonard may never again become friends because of this event but please do not go back home because of it." Sheldon tried to say as he handed her the cold bowl, hoping it would comfort her where he could not. She took it and just looked down, she didn't feel like eating but the gesture was so nice, she wouldn't mind trying to eat.

"Why shouldn't I go home?" Penny mutters as she pokes the ice cream. Sheldon slowly removes the box and sits in its place. She doesn't look to him as he sits there for about a minute. It is within that minute that finds no reason to stay. Her job was terrible, the only friends she had were nerds, and she was alone. Leonard had laid some hard truths on her and she felt there was no reason to stay in Pasadena.

"I'll miss you Penny." She hears Sheldon say but it doesn't really reach her. Penny is too focused on the melting ice cream and the tears falling into it to hear Sheldon confess his feelings for her. He places a timid hand on her shoulder and gets up from the couch. It's about two minutes later that Penny notices her door is shut and her ice cream has melted and that her box of clothes and magazines has been moved. And she can't help but wonder if she missed something. Getting up she heads across to the boys' apartment and knocks. She believed her knock was far too soft and that Leonard might behind the door so she turns around, ready to go back and resuming packing all of her junk when the door opens and she pauses. "Penny?" Sheldon asks. And it is that soft voice that makes Penny turn around and lung forward, flinging her wild Nebraskan arms around the frail shocked scientist.

He stiffened up like a board and Penny just buried her head in his chest, unable to see the look of pure mortification on his face. "I wish I could go back and in time and never have gone out with him, never met him, never left home, never done anything." She cried. Sheldon remained quite still and shifted himself out into the hall while closing his own door behind him. He looked down at Penny and slowly brings up a hand to her back.

"There there." He finally manages to say but it's by far more cautious and uneasy than usual. And that was saying something.

"Please invent a time machine, Sheldon. Please stop my heart from breaking, stop me from making a fool of myself." She couldn't believe she was breaking down in the skinny awkward arms of Doctor Sheldon Cooper and yet she never felt more embraced, more understood. It was rather weird but totally not important. "Please." She cries, tightening her hold on the flash tee shirt the boy has on. She slowly pulls back and he just stares down at her and for a moment Penny wasn't sure what she was expecting.

"Penny," He begins to say. "I won't do that." And with that, his arms went back around the poor girl's trembling form. "I won't do that because if you go back and prevent Leonard and yourself from meeting, than you and I would have never met." He confessed. "And it is in thanks to meeting you that my life had changed for the better and I can only hope that one day you can say the same." But of course, whose life wouldn't be improved upon meeting Doctor Sheldon Cooper? "I know I'm being quite cold and childish to say that your broken heart is worth less than my benefit from your company but I believe that many sacrifices must be made for the greater good and I of course, fall under the latter category." He said. Looking down he saw Penny wiping her eyes with the back of her hand. "You have yet to propose a valid and thoughtful hypothesis for time travel Penny and I hope one day a device doesn't fall into your hands because all sorts of chaos would ensue because of your willy-nilly choices of second chances." He chided.

It took some time before Penny began to unravel what he had said just then, and back in her apartment only minute ago. "You'd miss me? If I left, you'd miss me?" She asked him.

"Not to mention your insistence on pursuing Leonard...if you were to date someone surely it would be the most suitable mate with the highest brain capacity." He mentioned, continuing his train of thought and not answering Penny's question because he found it to be a rhetorical one. "I am much smarter than him, my genius knows no bounds, surely your low rate education can understand at least that?" And it was with that question that got Penny to smile, lean up and pull his lips to hers.

The unspoken time travel conversation would take place in the future, many years down the road.

Penny and Sheldon would be sitting outside in a small park. They would be roughly ten years older than when they first met. Sheldon would be reading a comic while Penny would be sitting beside him, and they would be situated at a small picnic table. The sun would be warming the summer air and one would notice a small bump in Penny's stomach. Sheldon would pause after every five or six pages to look toward Penny with a look of mild curiosity and concern and even love. Penny would be on her phone or reading from a magazine. And the two would sit there in the park, enjoying the fresh air that Sheldon seems to deny enjoying even after going to the park more than just twice a month.

And a brief glance would be shared between the two, one that spoke of no need for a time machine. Sheldon knew that every mistake they had made had brought them where they were and he knew once something was perfect, you didn't mess with it. And Penny knew that despite the hardships of her past, she had ended up in the right place after all. But if either of them did have the technology for a time machine, they knew they would only change one thing, which would be that Sheldon would have greeted Penny before Leonard. But none of that matter now, though Sheldon couldn't help but feel a little protective of his Penny now. She thought it was cute and the two would just wordlessly go back to their reading, knowing that hypothetical time travel was nice but realistically it was unnecessary.