Disclaimer: I do not own Big Bang Theory or Sherlock.

Author's Note: This was written for the Saturnalia exchange over at Paradox. It was kind of tough to combine the two shows but I gave it the old college try. There aren't really any spoilers but Sherlock's rather lacking knowledge of the universe in episode three was my inspiration.

The Deductive Realization

The lecture had been long and excruciatingly boring. Penny had dozed off at least three times but unfortunately she couldn't stay asleep because the ancient wooden chairs were small and extremely uncomfortable. She wasn't sure why Sheldon had insisted that she come with him to watch Raj's lecture. It wasn't that she didn't want to support Raj but this was the fifth lecture that Sheldon had dragged her to in the last two days and everyone knew that she was worthless at these things. In fact the only reason Leonard, Howard, and Raj had pooled together to pay for her trip to London was so that she could keep Sheldon in line. Well as in line as Sheldon could be kept.

She had jumped at the opportunity imagining all of the sites she could see and all of the shoes that she could buy. She had even entertained a daydream that she would run into Prince William and he would fall madly in love with her, leaving Kate to make her his Queen. Penny could definitely deal with a few bald spots if they came with that kind of shoe budget. Instead she had spent most of the trip stuck inside lecture halls watching one boring physics lecture after another. And on top of that it had been raining all week long which did awful things to her hair.

Penny shifted trying to find a more comfortable position. Unfortunately the chair creaked and groaned causing Sheldon to give her a dark look. Through sheer force of will she managed to avoid sticking her tongue out at him. If he didn't want her making noise he should have let her take the double-decker bus tour of the city like she wanted. With a heavy sigh aimed at Sheldon, she turned her attention to the podium where Raj was speaking. She did find it interesting to listen to Raj speak without the influence of alcohol. Howard had explained that Raj could lecture because he wasn't able to identify individuals in the crowd. She didn't really understand how dozens of women could be less intimidating than one but poor Raj had issues, lots of issues.

Penny let her eyes drift across the crowd; of course there weren't exactly dozens of women here. There was a bigger crowd than she had expected though. Much more than had ever turned out for any of the lectures she had slept through at Cal Tech. Most of the attendees looked like she would expect for this sort of thing: bad suits, bad haircuts, and kind of sickly looking. Her eyes stopped on a man standing just inside the entrance. Unlike all of the other men who were wearing ill fitting plaid suites, he was wearing a very flattering long black coat which fit him like a glove. He had dark hair and cheekbones that could cut glass. Now that was something she could stay awake for.

Penny shifted around to try to get a better look which earned her another glare from Sheldon. This time she did stick her tongue out at him. She could only be expected to put up with so much after all. And by the time she looked back toward the door the man was gone.

That evening Penny found herself following Sheldon around a reception hall as they tried to find Leonard, Howard, and Raj. After Raj's lecture she had finally convinced Sheldon to let her take a tour of the city. She had been surprised when he had opted to skip a question and answer session with Stephen Hawking to go with her. Even she knew Stephen Hawking was a big deal so she felt a bit special that Sheldon spent the afternoon lecturing her about the Tower of London and Westminster Abbey instead of attending. Penny had felt special enough that she had even paid attention and had been surprised to find that when he was talking about history instead of physics, Sheldon was much more entertaining.

Leonard, Howard and Raj had been shocked that Sheldon chose to tour London with her instead of grill Stephen Hawking about his work on a real world warp drive but had been so happy that they had practically pushed the two of them out the door and onto the tour bus. They hadn't wanted to take the chance that Sheldon would change his mind not even taking the time to tell them where they would meet up for the closing reception.

By the time they finally found the others they were with the man she had seen at the lecture that morning. He seemed to be having an intense conversation with a not quite sober Raj.

"Hey," Leonard said as they joined the circle. "Did you have a good time?"

"It was great." Penny said smiling. "It even stopped raining long enough for me to take a few decent pictures."

"That's good." Leonard said before lowering his voice. "I'm sorry you got stuck with him all day."

"It was nice to have the company." Penny said defensively before nodding toward the mysterious man. "Who's that?"

"Some guy named Sherlock." Leonard answered as they made their way closer to Raj. "He has some questions about supernovas or something."

"What kind of name is Sherlock?" Penny asked.

"It's old English for 'fair hair.'" Sheldon answered loudly, moving to stand between Penny and Sherlock. "Not really an appropriate name for someone with black hair."

"It's an old family name." The man said turning around to pierce them with his gaze.

Penny nearly gasped when she saw that his eyes were pale grey. She felt mesmerized by the intensity in his stare. It was cold and calculating, almost like he was seeing everything about her and cataloging it away. Suddenly he didn't seem as appealing as he did unnerving. Penny pulled her sweater closed and crossed her arms defensively.

"It looks like your girlfriend is uncomfortable." Sherlock said to Sheldon.

"She's not my girlfriend." Sheldon said defensively as Leonard and Howard burst into laughter. Strangely enough Raj stayed quiet looking thoughtful. "Romantic relationships are nothing but an unnecessary distraction from work."

"And yet you are in love with the blonde." Sherlock said.

"Why would you say that?" Leonard asked still chuckling.

Sherlock sighed. "Is it really not obvious to anyone else? First, they arrive together. Second, he is carrying her bags."

Penny looked down at the bags dangling from Sheldon's hand. He had wordlessly taken them from her as they left the British Museum. But that wasn't unusual; he often helped her carry her groceries at home.

"He's from Texas." Howard interjected. "That's the way his mother raised him."

"Third, when they joined us he positioned himself in front of her so that I would know that she was off limits. Fourth, despite proclaiming the importance of his work, he spent the afternoon sight seeing instead of attending a session with the most prominent physicist here."

Penny was vaguely aware that Leonard and Howard had stopped laughing but she was focused entirely on Sheldon. Her mind was replaying their entire afternoon. He had agreed to spend what short time they had at the British Museum looking at ancient Egyptian jewelry and shopping in the gift shop. He had let her pick the restaurant for lunch and only made a few complaints about traditional English pub food screwing up his regularity.

"And lastly, he is much more concerned with what she is thinking than what I am saying. He hasn't taken his eyes off of her yet." Sherlock finished. "Now does anyone have a cell phone I can borrow? I need to send a text and my number might be recognized."

Everyone was too busy staring at Sheldon to respond and after a moment Sherlock disappeared into the crowd.

"Is it true?" Leonard asked angrily. He stepped forward and threw an arm around Penny's shoulders.

The possessive touch made Penny's skin crawl and she shrugged him off immediately. "What was that?"

"I believe that is Leonard's attempt at calling dibs." Raj offered, taking a deep drink from his champagne glass.

"Is that right?" Penny said in a deathly calm voice. "Well I am not a possession to be claimed. And we broke up a long time ago. You have no say whatsoever in who I do or do not date."

"Are you saying you would date him?" Leonard asked incredulously gesturing at Sheldon.

Penny turned back to Sheldon. One look at him and she forgot all about Leonard. Sheldon looked shell shocked. His face was beginning to twitch and he looked like loud noises might spook him.

"Sweetie, are you okay?" Penny asked stepping slowing toward him and carefully reaching out to take his hand. She half expected him to jerk it away or at least flinch at the contact but he just stared at their joined hands as though it was a math problem that needed solving. "Come on let's go back to the hotel and talk about this."

Penny gently led Sheldon away from his gaping friends. He didn't say a single word the entire way back to their hotel but he never let go of her hand.