Sheldon walked down the abandoned corridors of Caltech. Turning the corner, he finally caught sight of the entrance to the neuroscience lab. Opening the door, he was surprised to find the lights on and various machinery humming with life.

Who would be here on Christmas day?

A tall woman in a lab coat popped up from behind a large piece of equipment. "Oh, hello. May I help you?"

He hesitated, then mentally shrugged. Only a true obsessive would be working in a lab right now. Perhaps she could help. "I need my brain tested for abnormalities."

She walked around the table, a smile on her face. "Well, you've certainly come to the right place."

"Excellent," he said, taking a seat in a nearby chair.

Settling a pair of horn-rimmed glasses across her nose, the gray-haired woman removed a pencil from behind her ear, and readied her clipboard for note-taking. "Have you suffered any kind of trauma recently?"

Sheldon fiddled with his messenger bag, then looked up to meet her blue eyes. "I kissed my best friend two hours, thirty-three minutes, and twenty-nine seconds ago."

The woman cocked her head to the side. "I see. I have a number of tests available, but I'll need additional data to determine which one is best."

He nodded. "Of course. Penny gifted me with a priceless vintage comic book and as a result I was forced to fulfill her Christmas wish for a kiss to restore balance to our friendship paradigm."

"Could you please expound upon the kiss?"

The metal table felt shockingly cool to his suddenly sweaty palms. "I found it unsettling."

"Did you experience a release of epinephrine and norepinephrine into your bloodstream?"

The scientific terminology soothed him. "Yes. My heart rate increased substantially."

"Any other irregularities?"

"Usually, my mind is constantly in motion, busy generating formulas and algorithms to solve the mysteries of the universe. When I kissed Penny, all of that disappeared and I regressed to a Neanderthal-like state, enslaved by hormones." Spock would be so disappointed in him.

He could hear her pencil scribbling across the paper.

"Go on."

"I wasn't supposed to feel anything." He gripped the edge of the table, a surge of frustration running through him. "There is no logical reason for me to dwell upon the event nor for me to wish for a second opportunity."

She looked up from her clipboard, eyes narrowed. "I do have a procedure in mind for you, however I would need access to personal photos. Do you and your friend have Facebook accounts?"

Sheldon nodded. "Penny's page mostly contains photos of her cavorting about in drunken revelry."

"That will do. Please login to your Facebook page for me," she said, gesturing to a nearby computer.

He complied and with a few clicks, the photos were downloaded.

"It may take a moment for the software to integrate the new data into its system. Please follow me."

She took him into another room. It was cold and glaringly white, bare except for an MRI machine. He'd had one done when he was eight years old.

"Do you have any metallic implants in your body?"

He did. Unfortunately, it wasn't metal alloy adamantium. "I have a Mexican peso lodged up my right nostril, however, it was struck before 1992 and contains no magnetic material."

"Good. It won't be going anywhere soon, then," she said, gesturing for him to lay down.

He situated himself as comfortably as possible. "How shall we proceed?"

"After you've entered the machine, various photos will appear one by one on a screen above you. You don't need to respond in any way, just remain as still as possible. I will be monitoring your brain activity to determine whether there are any aberrations."

Sheldon exhaled slowly. "Will you look for lesions as well?"

"Of course," she said, with an encouraging smile. "We can look over the results together afterwards."

"That sounds reasonable."

She gave him a little wave and left the room. A few minutes later, the bed he was on retracted and he found himself inside. It was fortunate he was not claustrophobic. The machine gave a loud humming sound and as she'd explained, an image formed above him. It was a picture of a Union Pacific Bigboy locomotive. One of his favorite trains. It remained for ten seconds before fading away. The next one was of Penny making a kissy face. The third one was a visual representation of the Schwarzschild wormhole. It was lovely.

Sheldon soon lost track of time as image after image flared in front of his eyes. There was a loud clunking sound as the machine died down and the sudden silence felt oddly overwhelming to his ears. He jerked in surprise when the bed returned to its earlier position.

A female voice came on the intercom. "Whenever you're ready, please meet me back in the lab."

He laid there for a minute, allowing his eyes to adjust to the abrupt change in lighting, then retraced his steps to the lab. Equal parts curiosity and trepidation churned inside him. It would be best to go with a lower fiber cereal tomorrow.

The neuroscientist stood next to the metal table from earlier. A series of glossy black photos were laid out across the surface. As he moved to stand beside her, he recognized them as images of his brain, various areas lit up with activity.

Relief filled him. There weren't any lesions at least.

She waved a hand at the table. "These photos indicate your brain's response to various visual stimuli. The software has combined the results into specific categories. These include your career, hobbies, interpersonal relationships, and a random sample provided by the software."

He nodded. "How do the results look?"

"Good, although, there was one odd response, but I have a feeling it must have been a glitch of some kind."

She tapped a photo which indicated two starbursts. "There was activity in the visual cortex which is perfectly normal since you're processing images, however the left anterior cingulate cortex also lit up, which is odd. It meant you found the random image generated by the software particularly stimulating."

He swallowed. "What was the image?"

She gave a little laugh. "It was a picture of old vellum paper with Chinese symbols written on it."

"Oh." A vision of smooth skin and the dark bold lines of a tattoo briefly short-circuited his brain.

Hoping to move on to the main results, he pointed to a different photo which showed a great deal of activity. Three areas looked like small wildfires of red, orange, and yellow. He smiled. "This must have been when you showed me images related to my work."

Shaking her head, she pointed to a marginally less active image. "Actually, this is the one related to your career. You can see where the reward centers of the brain are lit up, indicating you receive considerable enjoyment from your profession."

He frowned, staring back at the photo that looked like an explosion of fireworks. "What about this one?"

She coughed. "The activated pathways in this image are regions of the brain that regulate dopamine, serotonin, and oxytocin."

He suddenly wished he'd paid more attention when Amy was babbling on about her work. "What does that mean?"

"Scientists believe these areas are active when a subject is experiencing romantic love."

"Which category was it?" he croaked out, hoping against hope it was his hobbies, though the hard knot forming in his stomach told him otherwise.

"This is how your brain responded to images of Penny."

Great Gallifrey. Her words rang out with horrifying finality.

Sheldon fell heavily into a nearby chair. This was so much worse than he'd expected. He was doomed.

She pulled up a chair across from him. "Let me assure you. There is nothing wrong with your brain. Love is a normal part of life."

He glared at her. "I'd prefer lesions over love any day."

"I've felt that way myself a time or two," she said with a grin.

Placing his now aching head in his hands, he massaged his temples. "I'll have to cut her out of my life," he mumbled.

She clucked her tongue at him and he was reminded strongly of his Meemaw. "I wouldn't do that if I were you. There's a good chance you'd experience considerable negative repercussions which could impact all areas of your life, including your work."

She tapped the brain image for emphasis. "These neural pathways of yours were dormant most of your life, but they're now very much awake. You can't just flip a switch and shut them off. It doesn't work like that," she said.

"Perhaps I can pretend to be unaffected."

The woman gave a low chuckle. "You might as well join the ranks of the Flat Earth Society while you're at it. You're a man of science, and it would go against every fiber of your being to deny the truth of the evidence before you. Science doesn't lie and it's clear your mind, body, and heart have chosen Penny."

He slowly shook his head. "I dislike change."

"Nothing is static. The very cells in your body are actively living, dying, and being replaced on a daily basis," she said as she gathered the photos and slipped them into a manila envelope.

She handed it to him. "It's up to you whether you wish to embrace this particular change or not."

He stood up on shaky legs. "I'll think on what you've said. Thank you for your help."

Holding the door open for him, she gave him a smile. "Everyone needs a brain scan now and then. Merry Christmas, Doctor Cooper."

He nodded and left the lab. He was halfway across campus by the time he realized he'd never told her his name.

After hours of pacing around his office, he finally came to a decision. He read over the document a final time, then pushed print. The machine gave a loud beep and a single piece of paper shot out into the tray.

Picking up the page, he slipped his messenger bag over his shoulder and headed for the exit. It was dark outside, half past eight according to his watch. It was going to be rather difficult finding a cab. He was in for a long wait. Fortunately, the area in front of the building was well-lit, so he needn't be concerned about vagabonds.

He pulled out his phone and stared at it. Maybe someone could come pick him up. The sound of an asthmatic engine filled the air. He knew it well. Sure enough, Penny's unreliable Volkswagen pulled up to the front of the building. It coughed to a stop and she got out, marching toward him purposefully.

His treacherous body responded by treating him to sweaty palms, heart palpitations, and a fluttery feeling in his stomach. If he died right now, it would be a tragic loss for the scientific community and the world at large.

"Sheldon, what the hell? It's been hours!"

"I was busy having my brain scanned for abnormalities."

She folded her arms across her chest. "I could've told you how weird your brain was without any tests at all."

He shook his head. "The results, though startling, were depressingly normal."

With a sigh, she turned away, then abruptly swung back to face him, narrowed green eyes focusing on him. "You never answered my question from earlier."

"What question?"

Penny poked him in the chest, right in the middle of his Green Lantern t-shirt, each word was emphasized with another tap. "Did you enjoy it?"

Heat filled his face. "I would have thought the answer was obvious."

Her hands went to her hips. Never a good sign. "Obvious? It's obvious you're insane! You kiss me, then run away like I'm diseased or something. You pretend to be sick to avoid me, then run away again to get your crazy head examined. Where in that giant whackadoodle mind of yours is the answer obvious?"

Sheldon hesitated. It was true he hadn't adhered to the rules of social protocol following the kiss. He'd been too overwhelmed by his own reactions to the event to even consider how his behavior had appeared to her.

A gust of wind caught on the paper in his hand and it fluttered out of his grasp to land at Penny's feet. He jerked forward to grab it before she could, but her Halo-honed reflexes were too quick for him.

She held it up to the light and her mouth fell open. Her next words came out an angry shriek. "A dissolution of friendship contract?!"

The paper crumpled into her fist as she advanced on him, eyes full of hurt. "You're going to throw away our friendship over one stupid kiss?"

"You misunderstand, Penny. Allow me to explain."

She threw the ball of paper at him and it bounced off his forehead before falling to the ground. "I understand enough!"

A surge of frustration filled him, and he caught her by both arms and yanked her to him. "No, you most certainly do not."

She opened her mouth to no doubt offer up more angry protestations, but he bent his head and crushed his lips to hers.

The world momentarily melted away.

Kissing Penny was a lot like operating a homemade CAT scanner, except instead of receiving radiation burns, he was experiencing an entirely different type of heat. It flooded through his system, sweeping through his brain and curling his toes, leaving shivery sensations in its wake.

He finally drew back for fear his brain would incur damage from lack of oxygen. He hadn't quite acquired the skills necessary for prolonged kissing. Penny's face was so close he could make out the tiny freckles across the top of her nose. Her eyes were still shut and he congratulated himself on his successful silencing method. Perhaps he'd get to utilize it again in the future.

"Will you allow me to explain now?"

Her eyelids fluttered open and her cheeks pinked. "Fine, but if you ever try to shut me up again like that I'll go Junior Rodeo on your ass."

Somehow the threat of 'Junior Rodeo' didn't sound quite as ominous as it once had. In fact, there was a small part of him that was intensely curious to discover exactly what that entailed. But that was for another time.

"I was hoping you might be amenable to dissolving our current contract so that we could replace it with an entirely different paradigm, one that is romantic in nature."

She exhaled sharply, staring at him with wide eyes.

The prolonged silence continued and icy cold terror gripped his heart. Had he misinterpreted her reaction to him?

Suddenly, a bright smile beamed across her face, rather like the rising suns of Tatooine. "Where do I sign?" she asked.

Relief caused a breath of air to whoosh out of him and he found himself smiling back at her. He looked down at the ground for the document and discovered he was currently standing on it. "I'm afraid I'll need to reprint it."

She snickered. "How about a verbal agreement in the meantime?"

"I believe you mean an oral contract," he said, choosing to ignore her exaggerated eye-roll. "I suppose that will have to do, though I find an official notarized document to be vastly superior."

A flashy car drove by and his Vulcan-like hearing caught the sound of holiday music. His arms tightened around Penny involuntarily.

He'd received a Christmas wish he hadn't known he'd wanted until now.

She grinned and lightly bumped her nose against his. "We could always seal the deal with a kiss."

Sheldon's heart sped up in response, but this time, he didn't mind so much. "That sounds eminently reasonable."

"Good," she said, wrapping her arms around his neck. "Because it's non-optional."

This time Penny kissed him and Sheldon had no complaints whatsoever.

Jessica walked toward a cherry red 1966 Ford Mustang convertible. A tall man leaned against the hood, humming along to "Santa Claus is Coming to Town".

Kissing him on the cheek, she lifted one brow. "Shouldn't you be sleeping?"

"Yes, but I discovered my beautiful wife was missing from my bed."

He nodded at the couple kissing in front of the building. "I see you've been busy."

She shot him a satisfied grin. "You're not the only one who deals in Christmas miracles, Nick."

The End