It is just another ordinary day for Leonard and Sheldon.

Indian food in hand, the two physicists climb the stairs. Their conversation is fairly lively, though forgettable for anybody lacking an eidetic memory. Suddenly, Leonard widens his eyes and nudges his companion.

"New neighbor?"

The door is open, revealing a pretty blonde. She is wearing less clothes than the weather requires. Leonard briefly misses his life of singlehood but shakes this off quickly. Even before Elaine he wouldn't have had the confidence to approach this beautiful girl.

Sheldon's eyes flit up and down quickly, memorizing her form. He rationalizes that taking in her appearance effectively will prove useful; no doubt, he will pass her on many a morning or afternoon. "Evidently," he says. He hopes that his physiological reaction—increased heart rate, dilated pupils, et cetera—will go unnoticed by Leonard.

Leonard opens his mouth for a second, but before he can vocalize his thoughts, the woman notices them. Her bright eyes seem friendly. "Oh, hi!"

"Hi," Leonard replies, taken off guard.

Sheldon's blue eyes are wide as he greets the woman. His lips stumble over the words, and the time flashes by until her door is closed. Puzzled, he frowns. This sensation is new—never before has he experienced difficulty speaking to, well, anybody. Is it possible that somehow, through contact with Koothrappalli...

"We should have invited her to lunch," Leonard says finally.

Sheldon looks at him. "Why? I was under the impression that one only offered food to females that one had a reproductive interest in. Please do not tell me that you are considering ending your relationship with Elaine. I simply cannot stomach another five weeks of your so-called 'emo music'."

He shakes his head fervently and pushes his glasses back up. "No! Just...I don't know. She seems nice. Do you...I mean, do you mind?"

Incredulous, the other man arches an eyebrow. "Mind? Are you asking if I would feel somehow disrupted by another individual interfering with our routine, consuming time that would otherwise be dedicated to more worthy pursuits, and potentially catalyzing another unintelligent reaction from your hormones that would lead to months of misery?"

"Uh…" Leonard begins, unsure. It's possible that Sheldon has suddenly learned sarcasm, he thinks to himself. "Yeah."

Sheldon considers this, incredibly quick brain scanning through a list of possibilities. Although his rational reasoning finds that the outcome was much more likely to be unpleasant, he is unable to stop his mind's eye from displaying the image of the woman...Penny, she called herself. He swallows, unfamiliar sensations creeping up his neck, and, realizing that Leonard is still waiting on an answer, gives a brief sigh. "I suppose not."

"Great!" Leonard enthuses, a genuine smile spreading over his face. "So go ask her."

Sheldon sputters. "Me?" he asks, indignant. "I believe that as this was your experiment, you should carry it out."

The other man looks at him. Slowly, he grins. "Elaine might take that as a sign that Penny—this really, really attractive woman—is a sexual threat."

Leonard knows that this is a language that Sheldon understands. The men share a long look, fraught with silent conflict and—at least on Leonard's side—halfway-thought prayers. The taller physicist gives a brief nod. "Very well," he says, obvious reluctant. He straightens even further and approaches the door.

Consciously, Sheldon is aware that there is no rational reason for him to feel uneasy. This woman is nothing to him. She is, admittedly, attractive, but he set such things behind him prior to his pubescence. Male-female dynamics were complicated, and could distract him from his true love: his work. And, he thinks, even if he was searching for a viable mate, Penny, obviously very desirable by most standards, would most likely view herself as above him. Although he is incredibly aware of the importance of his intelligence and accomplishments (and considers himself, if such things matter, a man of above average attractiveness), he has also consumed enough pop-cultural dramas and psychological journals to recognize that she would be considered "out of his league". Mentally, he huffs. As if any goal was above his drive and talent.

Still, the thought is somewhat depressing, and he refuses to consider this further as he raps at her door. "Penny," he says softly, an unpleasant sensation tickling his spine and tightening his throat.

She opens the door before he reaches the third set of knocks, a fact that rather irks him. Still, she has no reason to know his habits. Sheldon halfway hopes that she will never have cause to learn them.

"Hi," she says brightly, drawing out the last syllable. He notices that her hair is more tousled than before, presumably from her labor. "Sheldon, right?"

"Uh, yes." She has caught him off guard, and he curses himself for this. A female—a woman—nobody had affected him this strongly since his adolescence, and he was no less awkward than he had been at that time. "Penny," he adds, remembering a snatch of social conduct. She offers him a smile in return.

Sheldon attempts to phrase the question in a manner that she will appreciate. "I was wondering if you would enjoy eating lunch with Leonard and myself? We have already purchased Indian food, and it is not inconvenient for us to share this with you. Also, if you happen to be a fan of the acclaimed series Battlestar Galactica, and have not yet viewed the second season with commentary, I would be delighted to allow you to stay and watch the episodes with us."

Leonard watches with some amusement. Penny seems to have been taken off guard; she glances from Sheldon to Leonard and back again, but something is shining in her eyes. She smiles and replies, and something in her words tips him off. The way she sidles up to him, keeping her eyes trained on his except when she looks coyly away...there's attraction there, to be sure. He almost pities her, having seen other women try to start down that path with his unreceptive roommate. Then he catches a glimpse of Sheldon's face.

While, as usual, his expression is mostly indecipherable, a slight smile is tugging at the tall man's lips, and his eyes are bright in a way that Leonard only ever sees when Sheldon is engrossed in his work...or Star Trek. It's all he can do not to gape as Sheldon actually leans forward and rests his arm on the door to speak to Penny.

"Well, you really should begin with the first season," Sheldon explains seriously. "Still, if you insist, I will hardly deny you of your privilege to partake in an excellent series, unorthodox methods aside."

Penny can't help but smile, brushing away the tingles of a too-familiar sensation. She reminds herself that the last thing she needs is another man in her life, but his disarming blue eyes are creeping under her skin. Anyway, he's far too skinny for her, though he's got a nice height. Her heart does an unbidden little leap.

Still, she's not looking for love, or even (for once) a cheap hook-up. Somehow, she doubts that this man would settle for less than commitment, and she's not up for that right now. Friendship, though, that she can handle. She flashes him another smile, this one fully intentional, and accepts his invitation.

Maybe she tosses her hair over her shoulder flirtatiously. It hardly matters; he wasn't watching, anyway.

"Wow, this looks like some serious stuff," Penny breathes. Sheldon feels a puff of pride and turns to her. He had not expected her to appreciate his work—the women in his family never had, and he hesitated to call most of the CalTech females "women", especially that she-beast Leslie Winkle. "Which one of you did this?" She gestures to his whiteboard.

For this, she receives a genuine smile. "That's my work," he tells her, leaning against the whiteboard. Sheldon feels strange, in a way similar to how he imagines caffeine or alcohol might make him feel. Had he unknowingly ingested some substance? Normally, this thought would cause a rush of panic, but the overwhelming sense of calm (accompanied by anxiety, most mysteriously) keeps this feeling at bay.

Penny blinks her (objectively pretty) eyes and takes a closer look at the whiteboard. "Wow."

"Yeah, well, it's just some quantum mechanics," he says, and for some reason he knows that it's vastly important to him that she cares. Impressing people is second nature to Dr. Sheldon Cooper, prodigy in every way; getting them to care about what he does, well, sometimes he does not dwell on that. "With a little string theory doodling around the edges. That part there, that's just a joke, it's a spoof of the Bourne-Oppenheimer approximation."

She nods, peering at the incredible mass of numbers and symbols. Math had scared Penny ever since high school, but she knows that without stuff like this, electronics would be impossible. She wonders briefly what Sheldon really does, but she's afraid to ask and not understand, so she just smiles. "So you're like one of those...beautiful-mind genius guys?"

The man almost blushes. Huh, a shy guy. Who'da thunk. "Yeah," he says in response, looking up at her from beneath lashes to kill for.

Leonard watches in amazement. He was a scientist, and he couldn't deny the evidence before his eyes, although it contradicted everything he knew. Sheldon Cooper was most assuredly flirting with Penny. A strange, quick urge seizes Leonard. He wants to bring the attention back to himself, to remind the beautiful woman currently staring at his roommate that hello, I'm a brilliant scientist, too.

Then his mind sweeps back to Elaine, with her long dark hair and pouty lips. The way her face lights up when she laughs. Her passion for her legal work.

Leonard smiles and settles for simply watching the pair.

Sheldon blinks several times. "I suppose that the food will be cooling to room temperature."

"Yeah, we should eat," Penny agrees. Her stomach rumbles quietly, and she tries not to think about the last time she ate—or what the last thing even was. She has a sinking feeling that she blew another diet.

They all take seats. She notices that Sheldon seems very quick to take the end cushion, but she doesn't mind sitting next to him in the middle. It strikes her as a little awkward that Leonard takes the armchair. Maybe he has some sort of personal space problem.

She nearly moans as she lifts the food to her mouth. Leonard catches her expression and gives her a weird look. In response, she shoots him a playful glare.

Somehow the conversation gets around to her lack of a working shower. Leonard looks at Sheldon significantly. "Ask her," he mouths, raising his eyebrows.

The other man frowns slightly, cocking his head to the left. "Ask her what?" he replies silently. Penny hides a smile behind her fork full of food.

"Shower," Leonard returns, with some exasperation. Sheldon purses his lips, makes an unpleasant expression, and turns to Penny. It's Leonard's turn to conceal his grin.

"Penny," Sheldon says conversationally, as if they've known each other for years. "Would you like to utilize our shower, then?"

"Could I?" The blonde woman smiles, eyes lighting up. "I mean...would that be too weird? I don't want to like, intrude or whatever..."

His lips twitch. "N-no. There would be no...weirdness."

She looks at Leonard, who tries his best to look serious. "Is that okay?"

"What? With me? Yeah, sure, of course." He nods enthusiastically, unable to stop smiling. Great, she probably thinks he's some sort of pervert. It was just too hilarious to see Sheldon actually trying to get along with another person.

"Great! Thanks, I really appreciate it." Penny stands, stretching slightly. Her back is a little sore, and she rotates a shoulder to try and fix it.


She looks back at Sheldon. "Yes?"

"Just confirming—you do plan on retrieving your personal cleansers, shampoos, et cetera?" His expression is one of genuine concern.

Not sure what to make of this, Penny offers another smile. "Of course, Sheldon. Going right now."

"Okay. Good."


She begins to make her way to the door.

"Oh, I suppose I should retrieve a spare towel," Sheldon says, to nobody in particular. Leonard makes a gesture, as if to give him a go-ahead, but his roommate isn't even looking.

A few minutes later, Sheldon finds himself pacing nervously around the apartment. The sounds of the shower are impossible to ignore. He frowns to himself. Why has he never experienced this difficulty with Leonard? He feels very much not himself, for his mind keeps straying. Sheldon has trained his brain perfectly, to the standards of a performing animal; now, he seems more like a goldfish. The same concept returns to him, the thought of perhaps electing to leave behind his life of celibacy, and, well...

She is very attractive.

He does not think this within merely physical terms. Yes, she is pleasing to the eye, but there is more to Penny than that. This was immediately obvious to him. She was captivating, somehow interesting although he couldn't care less about the mundane details of her life. Simply the way she said the words made him want to listen attentively, filing away every tiny nugget of information.

On top of all of this, his stomach is strangely unsettled. Indian Food Day may be on its figurative last legs.

Leonard does not bother to hide his smile now, as his roommate paces back and forth. He knows that Sheldon is completely wrapped up in his thoughts, though he can only guess at the contents. He drifts back to the blonde currently in the shower and smiles. She may end up being the perfect fifth member of their group, after all.

End Notes: This will be a five-chapter story, with each chapter title being based on a musical interval. The intervals will decrease in size as we go along. Special thanks to bigbangtrans for posting the episode transcripts, of which I made liberal use.