Spoilers: Up to 03x15 - The Large Hadron Collision to be safe, events happen in a slightly alternate universe in the near future
Disclaimer: I don't own any part of The Big Bang Theory. I'm just borrowing their universe for my own entertainment.
Word Count: ~3500 (~13900 total)
Notes: Is it...normal to wake up to your brain writing TBBT fic? Mine did a little while ago. Not quite done with the whole thing, but I'm close. I had every intention of this becoming smutty but I think that's going to be for a different fic.

Much love and candy to San and kg for the beta and support.

(Also, I'm new to the fandom and haven't read everything out there, so I apologize if this ends up being like another fic. I didn't know, I swear!)

He gets stuck again in the middle of March.

As Sheldon explains what it is he's working on, Penny tries to listen, but she only gets about a quarter of the content--a marked improvement from when they first met--so it gets more difficult to really pay attention. She files away a few key words in her mental list of "Things Sheldon is Really Passionate About That No One Else Understands" to look up on Wikipedia later and tunes him out as he keeps going.

She thinks, instead, of high school. More specifically, high school English class, when they read Julius Caesar in turns, out loud. She remembers Denny Worthington, the class clown, melodramatically proclaiming, "Beware the Ides of March!"

Beware indeed.

The guys are understandably wary. They've been through this more times than she has, but she's a quick learner. This time, she remembers to watch where she's stepping. She doesn't need a broken hip to add to her ever-growing list of woes.

After 37 hours of Sheldon being even more insufferable than usual--which is really a feat, if you think about it--Leonard gives up.

Penny is leaving for work just as Leonard lugs a suitcase out of his apartment. There's an awkward moment when they see each other. Their breakup is still a little fresh and she knows he's still hurting, still looking longingly after her when they pass each other. She smiles uncertainly, points at his suitcase.

"Going on a trip?"

Leonard grimaces. "Not exactly," he says, pushing his glasses up. "Sheldon's being impossible."

Penny gives him a look.

"More impossible than normal, for him," he clarifies. "He's not sleeping, which means I'm barely sleeping, and I have a pretty intensive and important set of experiments to run at work in a couple days."

"Oh." She tries not to read into the forlorn look on Leonard's face as he looks at his shoes, tries not to think he's also leaving to take a break from seeing her all the time. "Where will you go?"

"Raj's."

She nods and there's another awkward silence.

"Hey, Penny," Leonard starts. "Would you..."

"What's up?" she asks, when he stops, a little part of her cringing at the idea he might be asking her out again.

"Would you, you know, look in on him a couple times? Just to make sure he's still...alive?" he manages.

Penny hesitates and berates herself for being so self-centered. Not everything is about her.

"Of course," she finally says. "I'll just poke my head in now, see if he needs anything."

"Thanks, Penny." And then he's off. She's kind of glad she has a reason not to make the trek downstairs with him.

She takes a moment and actually knocks before opening the door. Penny never knows exactly what she's in for when she enters their apartment and with Sheldon in the mood he was in she doesn't want to take her chances too much.

She needn't have worried. She's pretty sure Sheldon didn't hear her knock. Cautiously, Penny steps inside and waits for him to notice her.

A full minute passes and he's still silent, standing in front of his whiteboard.

"Sheldon?"

He whirls around, surprising Penny with his sudden movement. They stare at each other and the semi-vacant look in his eyes tells her he's not really seeing her. Most of his thoughts are still with the whiteboard. She waits for her presence to really register.

"What?"

Penny suppresses the urge to get annoyed at his tone. This is just the way Sheldon is when he's stuck on a problem.

"I'm about to go to work, do you need anything?"

"Nothing you can offer," he replies shortly before turning back to his work.

Penny makes a face at his back. "Okay, well, call if you need anything."

She waits a beat longer, not really expecting a reply but still a little annoyed when he doesn't acknowledge her departure. She rolls her eyes and heads to work.

It's a half hour until her shift is over when she realizes the guys haven't come in for dinner. It's Tuesday, they always come in on Tuesdays. Then she remembers Sheldon's the only one who really enforces that routine and with Sheldon being in ultimate Sheldon-mode, the guys probably took the opportunity to do something different.

But it also probably means Sheldon hasn't eaten. As she's picking up a check, she idly wonders if Sheldon has eaten at all since he got stuck.

"What are you so worried about, Penny?" she scolds herself. "He's a grown man, he can take care of himself."

Except when he can't.

Like now.

Blowing out a breath of frustration, she orders his barbecue burger to go with her own dinner and winds down her shift, grumbling about the pittance that is her tips.

The drive home takes longer than normal and by the time she's dragged herself up four flights of stairs, Penny's in half a mind to ditch Sheldon's dinner and just go to bed. She's halfway across the landing before her conscience gets the better of her. It would be a waste of food, she tells herself.

She doesn't bother knocking this time, but peers around the door carefully just in case. She doesn't know what she is expecting but what she gets isn't it.

Somehow, Sheldon's whiteboard collection has grown as if they'd reproduced on their own. The bookcase and the landing behind the couch are nowhere to be seen, blocked by a solid wall of whiteboard. And, as far as Penny can tell, just about every available space on said whiteboards is covered in Sheldon's impeccable writing.

The man himself is kneeling in his spot, facing the whiteboards, body half flung over the back of the couch, head lolling to the side.

"Sheldon, honey, are you okay?" she asks, stepping carefully into the apartment, shutting the door behind her.

"What are you doing?" she tries again when he doesn't answer.

"Trying to get a new perspective on this equation," he says, turning his head to look at her. She expects annoyance at her interruption, but instead she thinks he just looks tired.

"Well, take a break."

"Penny, I'm working on something very important, I can't take a break."

"You need to eat. Your body needs the energy and your brain needs the break."

"Penny--"

She holds up a hand. "Remember the last time this happened? You needed something mundane to break you out of it."

Begrudgingly, he grunts and nods, turning around to sit properly in his spot. "But it's Tuesday and Tuesday is Hamburger Day and if you're back from work that means it must be past nominal dinner time. Besides, even if I were to collect the others and go to The Cheesecake Factory, you wouldn't be there to serve us and that would be unsatisfactory. Who else there would I trust with the proper handling of my food?"

She smirks at his ramble and holds out a takeout bag.

Sheldon's eyes flick from the bag to her eyes and back.

Penny rolls her eyes and walks in, depositing the bag on the coffee table. "I brought your usual, Sheldon."

"Is the--"

"Yes," she cuts him off before he can start questioning the integrity of his dinner specifications. "Just eat it."

He gives her a look but pulls out the carryout container and opens it. Penny swears she only blinks a few times and the entire meal is somehow gone. Sheldon's neatly collecting his empty containers and placing them in the trash before she can even sit down and open her dinner.

"Thank you for bringing me my burger, Penny," Sheldon says and looks at her expectantly.

"You're welcome, sweetie."

And then he turns around again, staring at his whiteboards. Penny watches him for a moment before digging into her salad. She's surprised he ate so quickly, even more surprised that he thanked her, but what really gets her is the fact that he didn't complain one bit about the potential hazards of having meat that had cooled from an appropriately hot temperature while she drove home. Startled, she shakes her head quickly to banish the thought and wonders where it even came from. Clearly, Sheldon is catching.

Sheldon is still stuck the next evening and Penny really starts to worry.

"Are you sure there's nothing we can do?" she asks Leonard.

"Look, Penny, I know you're concerned," he says, voice sounding far away on the phone, "but this is just something he has to work his way through."

"Leonard, he hasn't slept in over three days, that can't be good for anyone."

She hears him sigh. "It's...rare he gets this stuck but trust me, nothing short of him solving the problem is going to get him to stop."

"What's the longest he's gone?"

"..."

"Leonard."

"Three days."

"And after?"

"He slept for nearly a full day, but he was fine."

Penny bites her lip in frustration.

"Just...thanks for looking in on him, Penny."

"Yeah," she says as goodbye and hangs up.

Tossing the phone on her couch, Penny flops back and stares at the ceiling. She knows Leonard is right but she can't help feeling a little miffed on Sheldon's behalf. Leonard is his best friend but he'd just abandoned him and, as far as she could tell, hasn't tried to help or look in on Sheldon himself or just be there.

Sighing, Penny grabs her keys and heads out to pick up the Wednesday night takeout.

Sheldon is standing on his head when she walks into the apartment with the food. Penny stops short, gaping, and wonders if he's finally flipped.

"Sheldon, what?"

"I'm making the blood rush to my head."

"Why?"

"When I right myself, the resulting disorientation will hopefully aid my cognitive functions in obtaining a different perspective on the equations."

She continues to stare and then shakes her head, not bothering to comment. Instead, she starts unpacking the food on the coffee table and waits him out.

It doesn't take long and Sheldon slowly turns himself upright, practically hugging the refrigerator as the "resulting disorientation" kicks in.

"Well?" she asks, popping the top off her order.

"Drat," Sheldon breathes. "I hadn't taken into account the shift in equilibrium."

Penny puzzles that out for a moment. "You're dizzy?"

"Yes," he manages, still gripping the refrigerator. "But, worse than that, I am still no closer to a solution than I was before I decided to try this technique."

"Imagine that," she murmurs before starting in on her meal. "Come here. Eat."

She can tell he wants to argue and she pins him with a stare. He fidgets but acquiesces. Again, the food disappears in an unnaturally short period of time and Penny wonders if there's somehow a small black hole in Sheldon's mouth. She nearly chokes on her food at the mental image.

"Penny, I hope you're not planning on requiring medical aid. I simply don't have the time to deal with emergency personnel or take you to the hospital."

She clears her throat and smirks at him. "Wouldn't dream of it, moonpie."

Sheldon just looks at her and her smile falters a little at the dark circles under his eyes. There's a weariness she can practically feel coming off of him and she wonders how he's even upright. It's as if his body is running on the power of his brain alone.

He returns to his whiteboard pondering and she finishes her dinner in silence. She's not really paying attention to him, which doesn't really matter in this case. But she is thinking about him.

Penny spends Thursday on Sheldon's couch, ostensibly reading a magazine but surreptitiously watching him. She entertains the thought of drugging him or perhaps hitting him over the head with her baseball bat just so he'd get some rest.

But instead, she watches and she notices the little things.

His shoulders droop more than normal, his head is a little less high. Even his face seems softer, as if he can't muster the energy to maintain his normally impassive and controlled features.

Occasionally, his fingers drum on whatever surface he's near. At first, she thinks it's random, but then his fingers move in a definite pattern and she realizes he's miming scales on a piano keyboard. They flutter off into some piece only he can hear and she gets caught up watching the strength and elegance of his long fingers as they play their silent music. She wonders if she can get him to play for her sometime--the drunken ditties he played in the Cheescake Factory forever ago don't count, she wants something more fitting for the elegance, something classical and poignant.

He has a minor breakthrough in the early afternoon and Penny gets so caught up in his excitement she doesn't mind when he all but shouts an order to her to go out and buy him ten more whiteboards (of his particular specification, of course).

He's through the third whiteboard when he falters and is inexplicably stuck once more. Penny practically melts into a puddle of frustration on the floor. Watching him work is exhausting. She can only imagine how much harder it is for him.

She starts to see cracks when she gets him to eat dinner. Penny's amazed it hadn't started sooner. As he's eating, he can't stop his left knee from bouncing. He starts repeating himself as she makes idle chit chat while they eat. She punches him lightly in the arm without realizing it, as if he was a record player with a skip that needed a nudge to get by to the next part. He doesn't even bat an eye, doesn't chastise her for touching him.

And his voice. His voice is quiet and low and he sounds like Texas. She doesn't notice how much she likes it until he stops talking, gets up, and stares at his whiteboards again. She's surprised to find her toes curled.

Penny drifts off just after midnight. She's vaguely aware of him flitting around the room as if he was some sort of physics hummingbird.

She wakes early, sunlight barely filtering into the room. At first she isn't sure why she's awake and then she realizes she can't hear Sheldon moving around. In fact, she can't hear anything at all. She sits up on the couch and she realizes two things.

One: she fell asleep in Sheldon's spot and lived to tell.

Two: she's covered by a blanket.

There wasn't a blanket on the couch when she fell asleep. Snuggling deeper, she takes a deep breath and Penny is somehow both surprised yet not that it smells like Sheldon. She looks around and finds him standing in front of a whiteboard between the kitchen and the hallway to the bedrooms.

"Sheldon?"

There's no reply, no indication that he's heard her. Penny stands and sheds the blanket, shivering slightly as the apartment's cool air hits her warm skin. She pads over and peers up into his face.

"Sheldon?" she asks again, worry creeping into her voice.

He's just standing there, not moving, barely breathing. She has to watch his chest for the slightest movement to tell that he actually is breathing. His face is completely blank and his eyes are staring straight ahead, unblinking.

"Sheldon? Sweetie? You're starting to scare me."

And she realizes she is scared. Scared that he's driven himself so far into his mind that she'll never see him again. Scared that there was something she could have done but she just wasn't smart enough to figure it out.

Unconsciously, she reaches out and grasps his arm. She can feel the warmth of his skin under the sleeve of his long sleeved undershirt and she relaxes slightly. But he doesn't respond, still doesn't react.

Her eyes trace the features of his face and she can see the fatigue written there in big bold letters. The circles under his eyes are so dark it looks as though he has two black eyes. His normally perfectly placed hair is ruffled a little from where he's run his fingers through it. She reaches up and gently smooths out the ruffles.

When he still doesn't respond, Penny feels an overwhelming urge to cry.

"Oh, honey," she whispers and her fingers fall to his cheek.

His skin is amazingly soft and she gently strokes his face, startled at the feel of stubble. Sheldon unkempt isn't something she's used to and she isn't sure she wants to get used to it.

The corners of his mouth are angled slightly down and Penny frowns to match it. She watches him, her arms framing his face. From here, she can feel his breath but feels no comfort that he's still a living, breathing human.

Because there's more to Sheldon than just those biological behaviors.

Because she wants Sheldon back to yell at her and annoy her and just be him.

Slowly, she steps up on her tip toes and places a tiny kiss at the corner of his mouth. She lingers for a long moment and pulls away with a sigh when there continues to be no response.

But as she's looking at him, her frown deepening, he does respond. He blinks.

Penny takes in a quick breath and waits. Nothing. She frowns again and waits some more. Still nothing. So she stands on tip toe once more and this time, she kisses the other corner of his mouth.

This time, he definitely responds, a breath coming out of him loudly as his eyes blink again, slowly, as if from some deep slumber.

"Come on, Sheldon," she urges. "Snap out of it!"

But all he does is stand there and sure he blinks a little more and breathes a little more regularly but he's still not there. Penny laughs to herself a little. She'd wanted him to do all the things that annoyed her and here he is, annoying her by doing nothing.

She waits a little longer before placing her hands on his shoulders and pulling herself up onto her toes once more and gently, but firmly, pressing her lips to his.

It takes a few seconds, but she feels him respond. Or, rather, not. She didn't think it was possible to be any less moving than unmoving, but somehow, Sheldon goes utterly still.

Suddenly, she feels his hands on her hips and he is pushing her. Her back hits the side of the refrigerator with more force than she anticipates, the breath coming out of her, breaking the kiss. Penny hears the cereal boxes rattle and sees Sheldon reach up to steady them before they fall.

And then their eyes meet. He is completely alert, completely there, and Penny wants to shout for joy.

But then Sheldon steps back, breaking the hold she has on him and she stops, arms reached out.

His eyes are flicking about wildly, not settling on anything for more than a fraction of a second and Penny thinks for a moment that she might have broken him. And then his expression changes and she's sure he's going to bolt for the bathroom to wash his mouth.

Instead, Sheldon pivots on his heel and grabs the closest dry erase marker and starts furiously scribbling on the whiteboard he'd been staring at earlier.

Penny almost feels offended that she's been ditched for physics when she notices Sheldon is smiling. He's actually, genuinely smiling.

He stands up straight abruptly, slapping the cap of the marker down loudly, and looks at her with a broad grin on his face.

"I did it!" he says. "I figured it out!"

And then he closes his eyes and he starts to fall and Penny barely makes it to his side before he hits the floor. He's heavier than he looks and Penny sags under his weight, settling for a slow fall. They end up in a heap, his head in her lap, fast asleep.

"Sheldon?" She prods at his shoulder, not really wanting to wake him up. But he's out cold.

Penny manages to extricate herself, arranging him as comfortably as she can before sitting by his side. She stares down at the passed out, exhausted physicist and shakes her head in wonder.

"Sheldon, Sheldon, Sheldon," she murmurs, smoothing out his hair once more. "What am I going to do with you?"

Penny frowns as the words come out. What was she going to do with him?

She studies his features as she mulls the question. He looks at peace, a small smile playing on his lips. Her hand traces the side of his face again and she runs her thumb across his bottom lip lightly. Carefully, though she knows she won't wake him, she leans over and places a kiss on his forehead.

She will deal with Sheldon later, when he's awake.

If he remembers.

"God, I hope he remembers."

The thought comes unbidden and she stuffs it aside before getting up and covering Sheldon with the blanket she'd used earlier. There is no way she is going to be able to move him so she settles for making him as comfortable as she can. She gets a pillow from the couch to put under his head and then she doesn't know what to do with herself.

Penny watches him for a few more minutes before she grabs her phone and texts the guys.

Sheldon's finally unstuck.

She quietly lets herself out of the apartment.

End Part 1