A/N: It is so long since I wrote Shenny fic, but I suddenly realised, Penny & Sheldon never featured in the previous sets of Christmas fics I wrote for 'The Mistletoe Effect' series, and that just needed fixing! So, how about going all the way back to Season 1 and throwing those two crazy kids together under the mistletoe? ;)

Disclaimer: All recognisable characters belong to Chuck Lorre, Bill Prady, and other folks that aren't me.

The Mistletoe Effect XIII. Penny & Sheldon

"Oh, dear Lord!"

As Sheldon exclaimed to himself for eighth time in as many times, Penny couldn't help but smile. Since her back was turned towards him while she fixed them both a drink, it didn't really matter. Besides, it wasn't as if she were laughing at the poor guy, it was just odd to her, how someone who said he didn't even believe in God or Christmas could keep on using a phrase like that when they were frustrated by something. Of course, it wasn't exactly strange that it was her causing his frustration in the first place.

"Is it really that bad?" she asked guiltily as she approached him then, a glass in each hand.

"I'm sorry, but first you would have to define the parameters you're using when you express 'that bad'," Sheldon told her with a stern look, even as he accepted the drink she handed to him and inspected it dubiously.

"It's exactly what you asked for," she told him definitely. "Diet Cuba Libre," she said, rolling her eyes and not even caring if he saw.

"Thank you," said Sheldon politely, taking a long sip. "Mmm, delicious," he said with a smile, placing the glass down on the side table away from Penny's laptop that he was still working on, two long hours after beginning. "Now, in reference to your earlier question, this computer was an absolute minefield of malware, spyware, bloatware. I am frankly surprised it lasted this long without losing functionality entirely."

"Ugh, that sounds bad." Penny sighed as she sat down beside him, sipping her wine as she leaned over to see what was happening. "But you're fixing it, right? Please tell me I don't need a new one. I really cannot afford that right now, and God knows, I can't rely on Santa this year."

The way Sheldon looked at her then, she was sure he was actually wondering if she was serious about believing in Santa. She opened her mouth to tell him she didn't, but then he suddenly looked back at the computer and began clicking away again. There didn't seem to be any point after that.

"I've removed everything that could possibly be causing problems in the system. Since you already told me you're not the 'backing up type' I took the liberty of setting up an automatic backup to the cloud for all your files, including pictures, video, and documents. I personally also back up to an external hard drive, but that would require you going to the effort of physically making a back up-"

"Not gonna happen," said Penny with a dismissive wave of her hand.

"As I thought." Sheldon nodded once. "I'm done," he declared then, sitting back in his seat and picking up his drink once more.

"It's all fixed up?" Penny double-checked, reaching for her computer and clicking at the mouse. "My God, it actually does stuff when I press the buttons!"

"Yes, well," said Sheldon dubiously, "please try not to click on anymore random pop-up advertisements. They are the online equivalent of strangers offering you candy if you get in the van and I would've hoped you had more sense than that, Penny."

She wasn't entirely sure whether to be insulted or complimented by those words. He thought she had more sense, which was a good thing, but did he mean he now realised he was wrong? Penny knew it would only give her a headache if she tried too hard to figure out, so she let it go. After all, Sheldon had just done her a huge favour.

"Thank you, Sheldon. I mean it," she said, turning towards him and somehow surprised to find him so close, despite the fact she was the one who had sat down beside him.

She ought to have known she hadn't left much space between her leg and his own, but distracted by the computer screen, they both seemed to have been oblivious, until now.

"You're welcome, Penny," he told her as their eyes met.

Swiftly, he shoved his glass to his lips and drank down at least half of his Coke, as if his life depended on taking another sip and then another. He looked awkward and weird, which wasn't so strange for Sheldon, but Penny was sure she hadn't seen that particular look on his face since the first day they met. When they stood either side of his white board and she compared him to the guy from A Beautiful Mind.

Back then, she remembered thinking he was really cute for a nerd. She still thought that sometimes, when he wasn't being a little too over-the-top with his weird, neurotic behaviour. Moments like this, when he was being all nervous and... well, cute around her, it was frankly adorable.

Turning to put the laptop back down, Penny spotted the decorations lying further across the coffee table and couldn't help herself. Reaching for the plastic sprig of holly entwined with another plant, she found herself smiling as she casually twirled it in her fingers and faced Sheldon on the couch again.

"So, you guys don't do much for Christmas, right?" she said, feigning innocence. "I mean, Leonard mentioned something..." she trailed off, playing with the decorative plants in her hand yet.

There was no way she would pull that kind of trick with Leonard himself. Penny still remembered Halloween and the terrible drunken kiss that she had no wish to repeat. Sheldon was a whole different ballgame. She might have wondered if he was even capable of any romantic or sexual feelings at all, but there were times when he looked at her and she was sure there was something going on in there. Today, she wondered, if she might just manage to find out. Christmas was a time for miracles, right?

"You know, many of the traditions that most people associate with Christmas are not in any way Christian," Sheldon told her, placing his drink back on the table as he crossed his legs and got comfortable again. "In the pre-Christian era, as the winter solstice approached and the plants died, pagans brought evergreen boughs into their homes as an act of sympathetic magic, intended to guard the life essences of the plants until spring. This custom was later appropriated by Northern Europeans and eventually it becomes the so-called Christmas tree."

"Well, what about this?" Penny asked as innocently as she could, showing him what she held in her hands.

"Actually, the holly does have a Christian connection," Sheldon explained. "The berries are often said to represent the blood spilt by Christ at his crucifiction, and the prickly leaves, his crown of thorns."

"Right," said Penny nodding her head as she scooted a little closer, "but what about mistletoe?"

She half-expected Sheldon to call her out on her mischief making. In a way, she was being kind of obvious, widening her eyes and fluttering her lashes. Of course, just because it would be obvious to any other man in the world, it probably wouldn't be to Sheldon. He was decidedly not like any other guy Penny had ever met.

Clearing his throat loudly, Sheldon eventually gave an answer. "Ah, mistletoe, the common name for obligate hemiparasitic plants in the order Santalales," he explained, "specifically phoradendron leucarpum in the continent of North America."

"But does it mean anything real?" Penny prompted, biting her lip as she waited for his explanation.

Sheldon seemed to be having trouble concentrating, which was interesting. Of course, when he started talking again, in pretty graphic terms about what mistletoe used to mean, Penny started to regret asking.

"Pre-Christian cultures actually regarded the white berries as symbols of male fertility, with the seeds resembling semen. It was the Romans who associated mistletoe with peace and love and began hanging it over doorways to protect the household, particularly as part of the Saturnalia festival."

That was really unromantic and kind of gross, but Penny intended to get to the good part before too much longer. She was about to ask about the kissing tradition, when suddenly Sheldon continued anyway.

"Of course, in the Christian era, mistletoe in the Western world became associated with Christmas as a decoration under which lovers are expected to kiss," he told her, and Penny was almost certain he had moved a little closer as he continued. "The custom of kissing under the mistletoe is referred to as popular among servants in the late 18th century in England. The serving class of Victorian England is credited with perpetuating the tradition which dictated that a man was allowed to kiss any woman standing underneath mistletoe, and that bad luck would befall any woman who refused the kiss."

"Wow," said Penny, no acting required by now since she really was weirdly impressed by all the information that had come spilling forth from Sheldon's lips. "That was... You really do know everything about everything, huh?"

"Penny." Sheldon shook his head. "No one person can know absolutely everything, but I guess I come as close as just about anybody you might've met to knowing all the knowledge in the world," he considered then.

Penny might've laughed if anyone else said that, sure it was a joke. Not so with Sheldon. He meant pretty much everything he said, struggling as he so often did with sarcasm and such. Maybe that was one of the things she liked best about him, how he was just honest and open with no side at all. It didn't hurt that he was so smart either, and cute, as she had noted before.

"So, mistletoe," she said, getting right back on track. "If a woman is standing under it, the man gets to kiss her, and she can't refuse?" she checked.

"Well, she can refuse, of course. It is every person's right to rebuff an advance of any kind," Sheldon said diplomatically, "but as I said, it was deemed to be bad luck, if one believes in such things."

Penny smiled at the way he said it, more so at the way he shied away from her now, turning to retreive his glass and quickly finish his drink. The next moment he was up off the couch and muttering about getting out of her hair or something. It was unfair to make him so jumpy and uncomfortable, Penny knew, and after he already did her such a favour today, she wouldn't push him anymore. Besides, as he would put it himself, if the shoe was on the other foot, she had done enough of an experiment here to prove her hypothesis. Sheldon had feelings, those kinds of feelings that meant he was attracted to women, Penny in particular perhaps. She didn't hate knowing that at all.

"Um, before I go," Sheldon said, turning back from the door, "would you like assistance in hanging your decoration?" he said, gesturing to the holly and mistletoe springs still in her hand.

"Oh, um, yeah, I guess," said Penny, shaking her head free of thoughts as she got up and came over to him, handing off the decoration.

Sheldon smiled, looking above the door and reaching up there to place the holly and mistletoe in its proper place, so it would hang in the doorway. Then he opened the door and stepped out into the hall.

"Thanks," said Penny, standing on the other side of the threshold facing him, "for the computer help, and the decorating help too," she said, gesturing up.

"You're welcome, Penny, on both counts," Sheldon told her, nodding once before turning away.

Penny was about to close the door when she suddenly realised he had stopped walking. She barely got a chance to breathe before Sheldon was all up in her personal space, his arm going around her and pulling her close as his lips descended and landed on her own. It was a brief kiss, but not without feeling. Actually, by the time Sheldon pulled away again, Penny felt more than a little weak in the knees.

"Um... I... You're just full of surprises, Sheldon Cooper," she told him, finally catching her breath.

He didn't answer that, just stared at her a moment and then smiled. "Merry Christmas, Penny," he told her, with unexpected sincerity, given he had no real love for the occasion himself.

"Merry Christmas, Sheldon," she told him anyway, unsure what else she could or should say after what just happened.

Watching her neighbour head back to his own place and let himself inside, Penny found she was still stuck to the spot long after Sheldon had closed the door. Her eyes drifted up then, to the mistletoe hung above her own door. She really should get that down before Leonard decided to come calling, but if she ever heard Sheldon's distinctive knock at her door, maybe she would toss it back up there, fast!

The End

A/N2: If you liked this and have any interest in reading similar fics for the fandoms of Timeless, Hart of Dixie, or MCU, keep a weather eye on the horizon - they will be showing up on this site between now and Christmas. Merry Christmas, Happy Holidays, Seasons Greetings, as is applicable to you and yours :)