A/N: Your acceptance of this story has truly been remarkable. Thank you. Time to wrap up some loose ends. *Lynn

xTBBTx

"We ought to do something as couples more than just movie night," Penny said before taking a sip of her coffee.

"Leslie and I are game," Leonard replied.

"Well I most certainly am not," Sheldon sniffed as he washed his cereal bowl in the sink. "By defining the day or evening as something for 'couples' immediately excludes Amy and Raj from the activity. Were it a 'double date' or some other social coupling I'd be amenable, however."

"Who says they won't be a couple by the time we do something," Penny grinned. Leonard raised an eyebrow.

"Holding out something on us?"

"Not something specific. I've just noticed that two single doctor friends of mine are spending an aw-ful lot of time together."

"Well I can assure you their gatherings have been for the purpose of science as Amy is still in the midst of treating Raj for his selective mutism," Sheldon said a tad crisply.

"Not all of them Moonpie. They've been going out to eat a lot and yeah, before you get all, 'but Penny as living beings we all have to eat' there's a difference between eating at The Cheesecake Factory and eating at The Stella D'or," Penny said.

"Wow. Yeah Sheldon look how long we've known each other and you've never taken me there," Leonard said with a wink to Penny.

Sheldon put his bowl and spoon in the drain rack to join his glass. "You've never shown any inclination towards imbibing undersized portions set at appallingly high prices. If you wish to go I'm sure we can arrange a suitable evening."

"Umm I think you'd be better off going with Penny," Leonard said before taking a sip of coffee. Sheldon regarded his girlfriend.

"I hadn't realized you'd wanted to dine there."

Penny made her way to the door. "Na, I'm a simple girl with simple dreams. All I want someday is breakfast in bed."

"The next time you're ill I shall be at your disposal," Sheldon readily offered.

"Not what I was thinking." At this Sheldon blanched.

"Penny it's a little premature to be considering parenthood. I—"

"Try again," Penny said with a smile. "Thanks for the coffee Leonard." The short physicist gave a wave as his neighbor departed.

"I suppose I could make her French toast for her birthday," Sheldon thought aloud.

"You're being too literal," Leonard said as he made his way to the hall.

Sheldon stood by the refrigerator in thought. 'Breakfast in bed'. 'Breakfast in be—

"You get it yet?" asked Leonard from the bathroom. There was no response save for the quiet closing of a bedroom door. He smiled. "He got it all right."

xTBBTx

"All I'm saying is that it was pointless for DC to amalgamate the universes in Crisis on Infinite Earths because by its very nature the universe will continue to parallel and diverge," said Raj as he, Howard and Sheldon mounted the stairs.

"I agree. There's no way the multiverses could ever settle on a reality where George Clooney plays Bat-Man," quipped Howard. All three men giggled, snickered and chuckled respectively.

"Well said Howard," said Sheldon as he tried the handle on his door. It was locked. "Although to be contrary I can't conceive of a world where Green Lantern beats The Avengers at the box office." He unlocked the door and the trio entered.

"What if instead of Joss Whedon they got Joel Schumacher to direct The Avengers?" asked Raj.

"Guess it isn't challenging enough taking out a lone 'Caped Crusader' when he could zap the penultimate billion dollar conclusion to four different Marvel franchises in one fell swoop," Howard said as he sat on the couch.

"I thought you said Leonard had something to do at home?" Raj set his comic books by the door before sitting next to Howard.

"From what he told me. I'm not his social calendar." Sheldon took his comic books down the hall to his room. A moment later he came back, a puzzled look on his face. "Odd, he's not here. What could have been so important he'd miss new comic book ni—"

Both Raj and Howard turned to Sheldon; the lanky man's gaze veritably bore a hole in the corner by the DNA model. In a shot he was out the door.

"What's with him?" inquired Howard as he started going through his comics.

Raj smiled. "I think he realizes something else's missing besides Leonard."

Knock Knock Knock "Leonard and Penny."

Knock Knock Knock "Leonard and Penny."

Knock Knock Knock "Leonard and Penny."

"Door's open, Sheldon," came Penny's voice. He entered the room to find Penny on the couch surrounded by notebooks and various school supplies. Leonard was by the kitchen island standing next to his—

Sheldon was seething. "What's that doing here?"

"Leonard was slowly killing a forest showing me what I was doing wrong on paper so he brought over his whiteboard." Penny pumpkin grinned. "I gotta get me one of those."

"Indeed." Sheldon glanced at the Pythagorean Theorem nicely detailed on the board. "So aiding Penny was your 'something that came up' that caused you to miss new comic book night?"

"She snagged me by the mailboxes. I said I'd give her a hand before Halo," replied Leonard as he began twisting the marker cap.

Sheldon turned to his girlfriend. "Why didn't you ask me?"

"You've been busy with your grand poobah theory. I didn't want to disturb you," said Penny.

"Penny when it comes to academics I'm always at your disposal," Sheldon said in a hurt tone.

"You also said coming back to California meant access to five doctors and Howard. Leonard's here tonight. Believe me Sheldon you'll have so many nights of 'knock knock knock Sheldon?' you'll regret ever offering to help me."

"You're finished?" Sheldon asked Leonard. The shorter physicist shook his head.

"Got another half hour or so." At this Sheldon nodded.

"That'll give Raj and I time to go procure Penny a whiteboard."

Penny was puzzled. "I don't need one tonight, sweetie. Leonard said I could borrow his as long as—"

"Oh he did, did he?" Sheldon spat. "Why isn't that just noble of him to offer his services to a lady in distress?"

Leonard sighed. "Sheldon it's no big deal. I wasn't using the board and—"

"So you'd be pleased if this were reversed?" scowled his roommate.

The two men stared at each other before Sheldon turned to Penny with rather a stiff smile. "I'll return shortly."

"Ok, what the frak was that about?" asked Penny after Sheldon had left.

"I violated one of the cardinal rules," said Leonard with slight smirk. "There are two things you need to understand about whiteboards: one, no one is to touch your board but you; two, never let your girlfriend use another man's whiteboard."

Penny giggled. "Seriously?"

"It's a pledge we take before we're given our first dry-erase markers," Leonard said solemnly but with a twinkle in his eyes.

"Wow. You risked being tossed out of the Legion of Supergeeks for little ol' me?"

"I'm a sucker for a pretty face."

Penny smiled. "That you are. Say, is that a dry-erase marker in your pocket?"

Leonard laughed. "Back to work, missy."

xTBBTx

The sounds of two sets of feet ascending the stairs filled the landing until they turned the corner and walked the last flight to their hall.

"Well here we are," said Penny.

"Here we are," agreed Sheldon.

A little smile came to her lips. "At this point I usually ask a fella in for coffee."

"And I'd tell you I don't drink coffee," he replied.

"So then I'd offer you tea."

"I'd say I was not sick nor in distress."

"I'd think 'cute, but clueless'."

"I'd be wondering why you were frustrated as all I did was refuse a hot beverage. As far as I know it's a social convention but not non-optional."

"Then I'd sigh"—here she made a little sound—"and smile and say 'Goodnight Sheldon'."

"And I'd raise an eyebrow"—Penny giggled as he did so—"and enquire as to the status of our goodnight kiss."

"I'd probably give a big ol' grin and teasingly say, 'I thought you weren't interested?'"

"I'd adamantly refute that statement."

"How would you do that?"

"First I'd state I'd made no such indication either in word or action that I wasn't interested. Furthermore, in entering the social construct known as a 'date' I acknowledged there was a procedure to follow which concluded with a kiss should the evening have been sufficiently pleasing. From your words and actions during the night I decided you were satisfied with the turn of events and therefore expect a goodnight kiss."

"I'm impressed."

"Facts don't lie."

"So you kissing me is a fact?"

"Conjecture at this point, although I am hopeful."

"I'd be hoping too."

"For what?"

"For you to shut your pie hole and just kiss me."

"There's that."

Her lips were soft and warm as he covered her mouth. Together they moved: gently, lightly and for a moment they were all they needed to know and where they needed to be.

"Not bad, Moonpie."

Another kiss.

"Don't call me Moonpie."

One. Two more kisses and they parted. Penny fished out her keys from her purse and opened her door.

"Last call for coffee," she said with a kindly smile.

"Goodnight, Penny."

He waited until her door closed before letting out a deep but silent sigh. A moment longer and then he was across the hall and opening his own door.

"Hey Sheldon," said Leonard from the kitchen.

"Leonard." He dropped his keys in the bowl.

His roommate frowned. "You look pensive. Want a hot beverage?"

"I don't want to be a bother."

"It's no bother. Just let me finish loading the coffee maker for tomorrow and I'll put on the kettle."

Sheldon gave a gaspy laugh.

"What?"

"And you say I don't have a sense of humor," the lanky physicist said as he went down the hall to prepare for bed.

xTBBTx

Sheldon sat on the corner of his desk chewing on a Red Vine as he glanced over his whiteboards. He still wasn't getting the answer he wanted but at least he was quicker to discern when he'd lost track and so correct himself.

After five more minutes of contemplating he sighed and checked his watch. He was due for a break and he readily admitted he needed one. With a stretch he stood up and headed for the door. Sheldon had the sudden urge to go for a walk and he was never one to deny his body anything. Once out in the hall he nodded a greeting to Professor Webster before setting off around the corner and down a familiar stretch of hallway until he found himself outside his old office. Save for the name change to 'Dr. Rajesh Koothrappali, Astrophysics' the door looked the same.

Knock Knock Knock "Raj."

Knock Knock Knock "Raj."

Knock Knock Knock "Raj."

"Come in," said a familiar East Indian accented voice.

Sheldon immediately regretted not taking a deep breath before entering as the smell of sandalwood was extraordinary to his sensitive nose. Nevertheless he didn't want to be disrupted so he closed the door.

"What brings you to my humble abode?" asked Raj with a friendly smile. It truly was a blessing not having to share an office with Sheldon; that glow-in-the-dark ant farm really gave him the creeps.

"I was in need of a break and while out on my constitutional thought to drop in on my good friend and see how he's doing," Sheldon replied with a twitchy smile. Raj was immediately suspicious.

"I'm not finished with the last set of numbers you gave me," he said as a warning.

"I'm not expecting them before late next week. I'm working on my own project at the moment."

"Ah." Raj was immediately at ease. "How's it going?"

"Slowly. Still Rome wasn't built in a day." Sheldon scanned the bookshelves, frowning at the mix of distinguished scientists and hackney romance writers. At least he managed to banish 'Twilight' from the office before he left. "How about you?"

"Hmm?"

"How have you been?"

"Quite good actually."

"I see." Sheldon glanced at Raj's whiteboard. The equations were a little long-winded but the results were sound. He'd never tell another soul but having Raj as an assistant was moving the project for detecting WIMP annihilations ahead of schedule. "So Penny says you've been spending your leisure time with Amy Farrah Fowler."

So this is what this is all about. "A good part of it, yes. All of you have girlfriends or a wife so I've more time on my hands."

Sheldon nodded, trying to put out of his mind his mother's phrase implicating the devil's influence on idle hands. "It's obvious why you'd want to see Amy: she's charming, witty, fiercely intelligent—a superior woman in every way."

"So why aren't you dating her?" Raj asked as he put down his book to regard his friend.

"I was already—compromised—before I met her. I just hadn't realized it until recently," Sheldon said evenly.

"Amy was really hurt you know," said Raj.

"It wasn't my intent."

"It never is. We all enter relationships with nothing but good intentions, Sheldon. Sometimes they work, sometimes they don't. The only thing we can do is try to be faithful to our principles and let Kamadeva bless our hearts."

Both men eyed each other.

"Be good to her," Sheldon said at last.

"Sheldon we're just friends."

"Raj—"

"Besides, you don't have to tell me that. She's amazing."

Again Sheldon nodded. "I should get back to my work."

Raj shook his head as his friend closed the door. He couldn't believe he'd gotten the Sheldon Cooper equivalent of 'mess with her and I break your kneecaps'. Sheldon really had to be crazy to imagine Amy interested in Raj.

"What am I saying? Sheldon is crazy." Raj chuckled to himself and went back to his book.

xTBBTx

Knock Knock Knock "Leonard."

Knock Knock Knock "Leonard."

Knock Knock Knock "Leonard."

Leonard sighed. Times like this he was glad his vision was bad enough that he couldn't read the time on his clock because if he could he was sure he'd murder Sheldon the minute the tall man entered the room. "Yes Sheldon?"

The door opened and Sheldon entered. "I hope I'm not disturbing you."

Ok now Leonard wanted to know what time it was. He put on his glasses and was greeted by 'two thirty five' on his clock. "Why would you be disturbing me? I was only sleeping."

"Fair enough," Sheldon replied, oblivious to the sarcasm. "Leonard I've been reading about coitus from a variety of sources and while they've provided a clear outline for what to expect when things go right the information gets sketchy when it comes to bedroom faux pas. I was unsure how to proceed with the research until I thought of you and all your disastrous exploits." He raised himself on the balls of his feet with his hands clasped behind his back. "I need you to tell me what to do if coitus is less than satisfactory."

"Gee thanks a lot." Leonard rolled onto his back and put his hands behind his head. "There's a lot that can go wrong before, during and after coitus. Can we narrow down a timeframe?"

"Perhaps we should go in chronological order."

"Ok first thing is to make sure the mood is right."

Sheldon raised an eyebrow. "What is this 'mood'?"

"Your date—in this case Penny—needs to be in the correct psychological and emotional state for her to desire coitus," answered Leonard.

"As her tendency is to initiate I've never had sufficient opportunity to ask her state of mind," Sheldon shrugged.

Leonard smiled at his own memories of Penny. Sheldon was bang-on with his observation. "Ok, so she's willing. The next thing is to see if you're willing."

"My pulse rate is usually elevated and my sweat glands are engaged as my body feels flushed. I find myself short of breath and my genitals feel constricted in—"

"That's good," Leonard said quickly. "We'll say you're interested. Ok, then it's all about foreplay."

"Kissing, licking, sucking, nipping," Sheldon said matter-of-factly. "What if I have difficulties?"

"With what?"

"All of it."

Leonard grinned. "Well that's why you've got to keep communicating. Let her know how beautiful she is and how turned on you are and how much you'd like to please her."

Sheldon was puzzled. "Whenever Penny and I engage in non-coital sexual behavior she likes silence or at least appreciates the quiet in lieu of listening to your continual moaning."

"Did she say that?" Leonard sputtered.

"Not in so many words. I believe the phrase she used was, 'Nice to see you can shut your pie hole unlike—'"

"Ok ok. So you're with Penny and she wants to have sex and you want to have sex. Here's a crazy idea—have sex."

"We're skipping over the foreplay," said Sheldon as he began to pace. "I need to know what to do should something go awry."

"Since your entire game plan right now revolves around talking I can't see how things could get any worse. Just tell her how you feel."

The lanky man stopped to look at his roommate. "I don't think that's a good idea."

"Why? People like to know they're loved, Sheldon."

"Unless one was to prematurely 'reveal his cards' as Wolowitz would say. You're aware of the consequence," Sheldon said seriously.

"Eyah." Leonard paused. "Except in your case it's different."

"Explain."

"Think about it Sheldon: you're not having sex, you don't wine-and-dine her, you don't send her love notes or flowers or do things for her 'just cuz' and yet she's still with you. Hell you act like 'Sheldon' and she's still with you. Why would she be if she didn't love you?"

"I've learned there are many layers to emotions even if I don't grasp the subtleties," admitted Sheldon. "I concur that Penny has a measure of 'feelings' for me but I can't go so far as to surmise their intensity and act accordingly."

"If you can't show her and you can't tell her she might assume you're not serious. Normally the word is 'interested' but there's no doubt you are; the question is really whether you're prepared to act on your feelings. I'm not telling you to say, 'I love you Penny'. Just let her know how you feel."

After a brief moment Sheldon nodded. "You've given me much to ponder. Goodnight Leonard."

"'Night Sheldon."

If he knew the incessant knocking wouldn't drive him nuts Leonard would have looked into a better lock for the door long ago.

xTBBTx

Bernadette leaned over to give Penny a whack on the back as the waitress choked on her wine.

"What?" Penny sputtered

"I'm just saying it would put him more at ease," Amy said calmly.

Penny put down her glass and wiped the tears with her fingers. "And how am I supposed to tell him? 'I had an STD test today pass the salt?' Leave the results on the coffee table? Power Point presentation?"

"It would be preferable if you waited until the results came in so he wouldn't have time to ponder the implications," Amy replied.

"I was fine the last time I was checked so unless Leonard had contracted something and hadn't told me I'm in the clear," Penny said.

"'Should' be in the clear," amended Bernadette. "I'm Catholic Penny. Technically I was still a virgin on my wedding night if you know what I mean," she said with a wink. "You never know who'll fall off the wagon."

"This is Leonard we're talking about," Penny chuckled.

Amy raised an eyebrow. "Who'd ever have thought he'd land you?"

Penny looked to Bernadette who shrugged.

Book time for STD test, Penny typed into her phone.

xTBBTx

"So if the Cosmic Cube's back in Asgard how's Thor supposed to make it to earth for 'Avengers 2'?" asked Leonard as he took the 'Thor' dvd from the machine.

"The comics didn't say it was impossible to travel to earth without the Bifrost bridge only that it was difficult," Sheldon replied as he studied his whiteboard.

Raj frowned. "All I know is he'd better meet up with Jane Foster this time. He returns from another world and no phone call? Not even a text? What a jerk."

Howard tapped his best friend on the knee. "Speaking of messages Bernadette said to say, 'congratulations'."

Leonard looked at the astrophysicist. "For what?"

"It's nothing," Raj said dismissively.

"O-K," said Howard slowly. He didn't know what was going on but he'd wait to consult with Raj before he went further.

The sound of footsteps in the hall preceded Penny's entrance into the apartment.

"Hey all," she said cheerily. "Raj! The man of the hour."

He shook his head no. When he realized both Leonard and Sheldon were staring curiously at him he twirled a finger beside his head as he indicated Penny.

"Don't be all blushy," Penny went on. "Come on, let's see it."

"What are you talking about?" asked Leonard.

"Well I can tell you don't subscribe. This week's issue of 'People' is out. You know, the one with Raj's article. Julie always brings her copy to work so I flip through them."

"Congratulations," Leonard said to Raj. "Although I don't see what the big secret is."

Raj thought for a moment before he widened his eyes and shook his hands in the air.

"Ah," Leonard replied. "You wanted it to be a surprise. Sorry about that but you know what they say about news traveling fast."

Sheldon turned away from the board to address the room. "It's true. In fact Amy Farrah Fowler and I conducted an experiment where we issued two pieces of gossip and—"

"Ok, cat's out of the bag. Let's see it," Penny said excitedly, ignoring her boyfriend's glare as she cut him off.

Raj shrugged and held out his empty hands with a smile.

"Oh, don't worry sweetie I snagged Julie's copy," Penny said as she plunked her schoolbag on the arm of the couch and began searching for the magazine. Looking horrorstruck Raj shook his head adamantly as he tried to dissuade Penny from her course of action.

"It's no big deal, Raj. God it's not like you're on the front cover or anything like that. Ah! Here it is." She pulled out the magazine and began flipping through the pages.

"Still it would be nice to be in 'People'," said Howard.

Leonard was incredulous. "Howard, you're going into space."

"Yeah but how many hot chicks read my synagogue's newsletter?" He winked as Leonard rolled his eyes.

"Here it is." With shoulders lowered Raj moved aside so Penny could hand the article to the engineer.

"Nice picture," Howard began. After a moment his mouth dropped open and he began chuckling.

"What?" asked Leonard, smiling because of the look on Howard's face. The physicist scooted around to the back of the couch so he could read over Howard's shoulder. At once Leonard started to choke as he did his best to reign in his laughter.

"It seems there's amusement to be found in your article," said Sheldon as he scribbled an equation on the board.

"Sheldon—" Leonard began but Howard quickly shut him up.

"No, no, let me do the honors." He got up and crossed over to his tall friend and held out the magazine.

"No thank you," Sheldon said. "If it were a scientific publication it would be another matter but as it's just common tabloid stock I'll skip it."

"Too bad," Howard drawled. "Because you're mentioned in here and—"

"Give it to me!" At once Sheldon snatched the magazine and began to read. A split second later he glared murderously across the room at Raj, who was curiously standing in the open doorway. The astrophysicist was sheepish as he shrugged apologetically before turning and running down the stairs.

"You're wrinkling the magazine," Penny growled as she took a moment to pry it out of Sheldon's hands. She glanced at the article. "I didn't know you were in here?"

"It's kind of subtle," Howard chortled. "You know how humble Sheldon is."

"Though I think the word 'outraged' is more applicable at the moment," Leonard said with a bit of sympathy.

At once Penny's mouth formed an 'o'. She glanced at Leonard before reading the end of the article aloud: "'So what's next for our dashing doctor? He's decided to take a break from Neptune and is assisting a colleague in searching for signs of the early universe known as dark matter. We know he'll have a 'Big Bang' of a time doing it.'"

"'Assisting a colleague'?" seethed Sheldon. "I'm the reason why he's employed and still living in the country!"

"Don't take it to heart sweetie," Penny soothed. "They're just fluffing up his story to make him sound better."

"At my expense," Sheldon grumbled.

"Well it's not like they mentioned you by name," said Leonard.

Sheldon put his marker on the whiteboard ledge. "So which is worse, Leonard: having my name out there as Koothrappali's lapdog or having his name on the mouths of mainstream America's lips whenever anything I discover about dark matter makes the news?"

"I thought you didn't give a damn what ordinary folk thought?" Howard reminded him.

"I care about what I think," Sheldon spat. "And I think this is a load of hooey." He stormed down the hall. The three remaining friends winced at the sound of a slammed door.

"Sheldon," Penny called as she crossed the room to follow her boyfriend. "Come on sweetie."

"You think Raj knew?" Leonard said. Howard gave him a crooked smirk. "Yeah, silly to ask."

xTBBTx

The door opened and Leonard entered the room. He spotted Penny reclining on the couch reading a magazine while Sheldon stood as still as stone in front of his whiteboard. Carefully he closed the door without making a sound and gingerly placed his keys in the bowl. Creeping across the floor he stopped behind Penny and put his mouth close to her ear.

"How long's he been like this?" he said softly.

She shrugged. "Since I came in at least." Leonard nodded.

"He's been struggling with this for over two weeks. I've offered to help but he's dismissed me so I give up."

"Except for the dark circles I'd be hard-pressed knowing he's in a bad way."

"That's because he's with you. You have an uplifting effect on people. You should see him at night sometimes," Leonard grinned. "Like walking in a minefield."

"If you're quite finished with your chat about my mental state can we have some quiet?" Sheldon said stiffly without turning from the board.

"'Kaboom'," Leonard said, gesturing with his hands the bomb's explosion radius. Penny shook her head as she smirked before returning to her magazine. As for Leonard he got a bottled water from the refrigerator and stood behind his stuffed chair in order to get a good look at Sheldon's equation.

"Clever use of the time constant," Leonard said after a few minutes. "I see you're trying to maneuver out from the elegant sequence to something akin to—"

"—The Feynman diagram, yes," Sheldon agreed.

Both men stood in thought.

"Have you tried substituting the structural construct for—"

"I've made corrections and substitutions. I've used time dependently and independently. Multi-Parameter Case and Hamiltonian. I've even tried a Lorentz invariant field to no avail," Sheldon grumbled.

"'Lorentz invariant field'?" asked a puzzled Leonard. "How does that even apply?"

"It doesn't." A pause. "I just wasn't going to let Dennis Kim be right a second time."

"Ok then. How about—"

"Leonard I'm doing enough questioning of my own work without needing to backtrack to answer your ineffective 'solutions'—and I put that term in very heavy quotes I may add," Sheldon said testily.

"Forgive a guy for trying to help," Leonard replied before taking a sip of water.

Sheldon turned to Leonard, his blue eyes icy. "When I have need for triviality I'll be sure to give you a—"

"Sheldon, I need a hand with something," said Penny as she got off the couch. There's a moment when she felt she was the only breathing creature in the apartment. "Sheldon," she tried again.

"With what?" he said at last.

"It's in my apartment."

"Penny I'm busy."

"It'll only take a few minutes then you can get back to discovering time or whatever," she said as she made her way to her boyfriend. She stood between the two men and waved to get Sheldon's attention. "Just for a moment. I'll bring you right back I promise."

His jaw clenched as he thought. "Don't touch my board," he said to Leonard. Penny took his hand and led him from the apartment, across the hall and into her own abode. She dragged him through the living room into the bedroom to the bed where she marched on her knees until she was up enough on the mattress to recline. The arm that held Sheldon's hand went taut.

"I don't have time for this, Penny," Sheldon said with annoyance.

"I want to talk to you," she said calmly.

"I can adequately converse from a standing position."

"Well I've been on my feet all day so you're ahead of me there," she replied. She tugged his arm lightly. "I just want to be eye to eye with you, stretch. Work with me will ya?" He continued to scowl at her. "The talk is non-optional so the sooner you get down here the sooner it starts." With a roll of the eyes Sheldon crawled onto the bed and lay down on his side facing his girlfriend.

"You may begin," he said tersely.

"Not until you drop the pissy attitude. I've done nothing to deserve it so I'm not taking it," she said back at him. He stared a moment before closing his eyes and nodding his head.

"I apologize," he said quietly. Sheldon opened his eyes. "Please proceed," he said with a poor attempt at a smile.

"What's going on Sheldon? Leonard tells me you're stuck on a problem again," Penny began.

"Not that it's any business of his but yes, I find myself at an impasse," he frowned.

"See, it's that 'it's not any of his business' thing that's got me involved. You're not formulating the Caramilk secret, Moonpie." He pursed his lips and started to speak. "Ok, ok, we'll skip the sarcasm," she interjected. "So what are you working on?"

"Penny I really doubt—"

"You're smart enough to explain to me what you're doing?" she asked with a little smile.

"You won't let this drop will you?" he asked simply.

"Nope."

Sheldon sighed. "There are some theories that can't be solved exactly. That doesn't mean we can't study them; we instead compute power series expansions in a small parameter. For example, quantum electrodynamics has a small parameter, called the fine structure constant which is given by—well it doesn't matter. Let's say it equals 'a'. Then if we want to look at a specific property—which we'll call 'T'—we use 'a' and 'T' repeatedly in a set formula—a whole whack of math—to come up with T (a)—an approximation."

"I actually got some of that," Penny said proudly. "Not enough to say I fully understand what the frak you just said but it's a victory." She squeezed his hand. "You know you've got a roommate who understands this stuff better than me."

"I'm aware of that," Sheldon replied.

"O-K. What about Raj? I'm sure he'd be—"

"No thank you."

"Too soon huh?" She shook her head. "You help them out all the time. What's wrong with having them return the favor?"

"I don't need their help, Penny," Sheldon said firmly and with a harshness to his voice.

They stared at each other in silence.

"You sound like an egotistical jackass, only you almost always sound like that so that means this is something else altogether." Penny gave his hand another squeeze. "Come on Sheldon, out with it."

At first he seemed content to let the silence speak for him but after a moment his eyes flashed to Penny's calm yet concerned expression.

"I don't mind helping them out on any of their problems. If they come to me with an interesting proposition I'm more than willing to collaborate. But after the trip to the Arctic I'll be damned if I let them go near my work again."

Penny nodded. "That's too bad you feel that way. Understandable though."

"Before I found out my data had been falsified my entire world had changed," Sheldon said softly. "By detecting the monopoles I would have surely garnered my Nobel Prize yet it was more than that. I've devoted twenty one years to understanding how everything came to be and why things work as they do. Sure I'm getting closer in solving the riddle but I admit there's a cloud of apprehension surrounding me as the years tick by. To think for a moment that my life's work had reached its apex and I was at the doorstep of knowing the structure of the universe only to have it be nothing more than a cruel ruse perpetrated by my 'friends'." He looked at her. "You're the only one who checked in on me to see how I was."

"I'm sorry," Penny said.

"In their defense they suggested their actions were better than their alternate plans of shooting me with a homemade crossbow or tearing me to shreds with teams of pack dogs." Sheldon's face turned thoughtful. "It's taken me some time but I've come to understand I can be—difficult. I've always been the object of ridicule and frankly I didn't care because my work was taken seriously. It's taken me nearly three years to regain what academic standing I have now and I won't risk my work." His blue eyes were steadfast. "I can't."

Penny nodded. "We'll get through this Sheldon. If it takes you working at the Cheesecake Factory or playing in the ball pit at the local Kid Zone to get this sorted out then so be it. Your work is you. I'm just along for the ride."

Sheldon narrowed his eyes. "That's not true."

"Hey, I'm not saying that because I'm feeling sorry for myself. It is what it is. You're here to solve the riddle of the universe and I'm here to remind you of your human heritage, Mr. Spock." She raised Sheldon's hand to her lips for a light kiss. "You really are a great friend, Sheldon."

"Of course I am. As my mother would say: 'Now Shelly, Jesus is all about forgiveness'. I quickly realized he said nothing about forgetting and as we know, I don't forget. Leonard might be my best friend but in some respects that's only in the context of his being the best of the lot; excluding Amy of course."

"Gee thanks," Penny grinned.

"I'm not counting you. You're another category entirely."

"And what would that be? Sassy-assed sidekick?"

"Necessity. You're absolutely necessary Penny." She blushed at the earnestness of his comment.

"Fascinating. Even though I have to say I don't advocate the use of absolutes"—here Sheldon laughed at her words said in an imitation of Mr. Spock—"in this case I'm willing to make an exception."

"Normally there'd be a rebuttal of 'whackadoodle' but as this is the most sensible phrase I've heard you utter in the past—" He never got to finish as Penny growled and moved into his comfort zone for a tactical and tactile response.

As it turned out, Dr. Sheldon Cooper was indeed ticklish.

xTBBTx

A/N: Wikipedia: Perturbation

Perturbation Theory: Caltech site.

My Two Cents: For my story I've tried to adhere to the spirit of the show in its entirety so I've avoided the one glaring misstep the writers made (imo) until now—the faking of Sheldon's monopole readings in the Arctic. The best way I could reconcile the event with the rest of the show is to have Sheldon compartmentalize his 'friends' and never put his core research at risk again. It's the only way I can see show-Sheldon remaining friends with them without alluding to the idea that he's at the mercy of idiot writers.

Thanks for reading!