Funny thing about realizing you're in love with your boyfriend's roommate. It makes you feel guilty about doing things you wouldn't have thought twice about doing before . . . like say crashing at your boyfriend's apartment, after you've locked yourself out of your own.

Penny's first instinct is to somehow break back into her own apartment. So, she starts crawling around the hallway on her hands and knees, in search of something . . . anything . . . that could be used to pick a lock.

And that's precisely how Leonard finds her . . .

"Uhhh . . . Penny, is this some sort of method acting technique I should know about?" He inquires dubiously.

"Oh, hey, Leonard," Penny says with a grin.

She's trying to appear casual . . . or at least as casual as one can look, while crawling around on the floor in her nightgown at 8 a.m. " 'Sup?"

"Ummmm . . . I'm going to work?" Leonard replies, with a shrug. "What are doing out here?"

"I locked myself out of my apartment," Penny admits sheepishly.

"Oh . . . well, come in then. You can call the Super from here," Leonard offers.

He's already fiddling in his pockets for his keys.

"OK? Thanks," Penny responds blushingly, as she walks past Leonard into his apartment.

"So, were you coming to see me?" Leonard asks, as he closes the door behind them.

"What?" Penny inquires nervously.

"You locked yourself of your apartment in your sleepwear," Leonard muses. "You obviously weren't planning on leaving the house. So, I assume you came to tell me something. What did you want to tell me?"

I want to break up with you, Penny thinks to herself.

"Well . . . no . . . I just . . . is Sheldon here?" She asks, her eyes frantically scanning the living room for signs of Dr. Wackadoodle.

"No, he's not, actually," Leonard replies. "He went to work, before I even got up this morning. I think he caught a ride with Raj. Did you know Amy broke up with him, last night?"

Penny winces. She knows this conversation is inevitable. But she's not ready to have it . . . at least, not yet.

"Mind if I use your phone?" She asks abruptly, in a feeble attempt to buy herself some time.

"Oh, yeah, sure," replies Leonard with a shrug, as he places the device into Penny's waiting palm.

Of course, The Super never answers his phone. So, she ends up text messaging him. This time, he replies right away.

"Toilet overflow on the 6th floor. I'll get to you, when I'm done."

Penny shakes her head. "I don't know why I'm surprised. This is the same guy who takes six years to fix a damn elevator," she gripes. "I'm sorry. I know you have to leave for work."

"Believe it or not, I don't actually have to be there until 10," Leonard admits, settling on the couch. "It's just that every day, beginning at 8 a.m., Sheldon usually starts following me around the apartment saying, 'It's 8:05, do you know where your Sheldon is? Well, he's obviously not at work, because Leonard won't drive him there,' Leonard sing-songs, doing a surprisingly impressive impersonation of his roommate. "That . . . and all the good donuts in the teachers' lounge tend to be gone by 8:30."

"Well, great. Then, you can keep me company," Penny offers unenthusiastically, as she reaches for the remote control, and starts absent-mindedly flipping through channels. "I'm never up this early. I have no idea what's on TV, now," she adds sheepishly.

They settle on a banal morning program, in which neither has too much interest.

"Hey Penny, has Sheldon seemed strange to you, lately?" Leonard asks, staring straight ahead at the television.

"Is that a rhetorical question?" Penny jokes, using the same language that Leonard had used in response to a similar inquiry she made, a few days ago.

"Haha," Leonard retorts, rolling his eyes. "No, I mean . . . at first, I thought he was just upset about his breakup with Amy, like last time. But he seems weirdly OK with that. He's just so secretive and distracted, lately. Sometimes, I'll catch him staring out the window with this dreamy expression on his face. In fact, if I didn't know any better, I would think he was . . ."

"You'd think he was . . . what?" Penny probes impatiently.

"Actually, in love with someone else," Leonard concludes with a shrug. "But it can't be, right? I mean, this is Sheldon we are talking about here."

"He's in love with me," Penny blurts out, before she can stop herself.

To Penny's surprise, Leonard responds to this admission by laughing?

"I'm glad the notion of someone being in love with me is so hilarious to you," Penny pouts defensively.

Leonard raises his palms in a placating gesture. "It isn't . . . it's just . . . come on! You and Sheldon? You two just don't mix. It's like Superman and kryptonite. Dr. Evil dating . . . Barbie."

"I want to break up," Penny says softly, looking down at the floor.

Leonard's eyes widen. "Oh gosh . . . Penny, I'm sorry. I didn't mean to offend you . . . I only meant that . . ."

Penny shakes her head. "It's not about what you said. It's just that . . . I don't think this is working. I mean, lord knows, we both tried. We've been trying, for a while now. But, sometimes, I feel like we're both just going through the motions of being a couple, without actually being one. You know? We don't make each other happy, Leonard."

Leonard nods silently, knowing instinctively that Penny is right. If he's being honest with himself, a part of him has seen this coming for quite some time . . . if only the rest of him hadn't been willfully ignoring the signs. "Did you ever love me at all?" He asks sadly.

"Yeah, I think I did," Penny muses. "Back at the beginning, when you were the loveable, eager-to-please nerd across the hall . . . and I was the naïve waitress, desperate for a guy who thought of me as more than a brainless pair of boobs. We were exactly what each other needed, at the time. But we've both changed so much since then. We've grown up. We've grown apart. It happens."

"There's someone else," he replies.

He doesn't phrase it as a question . . .

"Yes," Penny admits. "Leonard, you should know that Sheldon didn't act alone, when he put that computer program on your phone. I asked him to do it. I was the one who thought you and Amy were having an affair. Sheldon was just covering for me, because . . ."

"He loves you," Leonard concludes. "And you're falling in love with him."

"Not falling," Penny corrects. "Already fell."

All of the sudden, it all makes sense to Leonard. Sheldon's strange behavior lately . . . his sudden breakup with Amy . . . the way he'd catch Penny's and Sheldon's eyes following one another across the room, when they thought no one was looking. He doesn't know how he could have been so blind.

"Leonard, I'm so sorry," Penny exclaims, reaching out to put her hand on her now ex-boyfriend's shoulder. "We never meant to hurt you."

Leonard flinches from her touch. "Don't . . . please don't," he pleads. "I'm going to go to work," he says, rising from the couch. "Feel free to stay, until you can get back into your apartment," he offers.

Then he's gone, and it's over. It was both easier, and harder, than she thought it would be . . .

The minute Leonard gets into the hallway, his cell phone rings. It's Amy. "Are you OK?" She asks him.

"Not really. Penny just dumped me for Sheldon. I feel like I've been warped into some alternate universe," Leonard admits.

"I know," Amy replies sympathetically.

"You knew this was going to happen?" Leonard inquires.

"I had a hunch," Amy answers. "Hey, listen, do you have anywhere specific you need to be right now?"

Leonard looks at his watch. He's still got an hour before he has to be at work. And yet, a part of him has already decided to call in sick. "Honestly, no," he replies.

Amy smiles. "Yeah you do. You're coming over to my apartment, where I've concocted the perfect cure for the broken hearted."

"You and I are going to drink until we pass out?" He asks hopefully.

"Better than that," Amy answers mischievously. "I've got three words for you, buddy, 'Downton Abbey Marathon.'"


Two hours later, Penny is at Caltech, standing outside Sheldon Cooper's office. She barges in without knocking . . .

Sheldon's eyes light up the minute he sees her. Then, he remembers she belongs to somebody else . . . his best friend, no less . . . and his expression hardens.

"You're in my office. My office is a sanctum dedicated solely to the pursuit of genius, and the study of theoretical physics. You cannot be in my office," he says sternly.

"Tough titty, Sheldon. I'm not leaving," Penny insists, folding her arms across her chest.

"Tough titty?" Sheldon repeats, a hint of amusement creeping beneath his posture of stoic annoyance.

"What the hell is this?" Penny asks, slapping the Custody Agreement on the desk in front of him.

Sheldon looks at the stack of papers calmly. "Why, it's a Custody Agreement, between myself and Amy Farrah Fowler," he replies matter-of-factly.

"I know what it is," Penny replies. "I'm asking you what it means."

"Well, I think that's pretty self-explanatory," Sheldon answers.

"Why don't you break it down for me, Sheldon?"

Sheldon takes a deep breath. "Very well. I've recently terminated my Relationship Agreement with Amy Farrah Fowler. Shortly thereafter, the two of us decided that it would be in the best interest of all involved to . . ."

Penny walks briskly around the desk, so that she's standing right above the physicist. "Are you in love with me, Sheldon Cooper?"

Sheldon's face turns beet red. "What? Well I . . ."

"It's a simple question," Penny interrupts. "Are you, or are you not, in love with me?"

"Yes," Sheldon blurts out, almost angrily, surprising even himself. "Yes, Penny I'm in love with you. I love your voice. And the way you laugh . . . and how your brow crinkles, when you get mad."

"I love the way make spaghetti, and hot cocoa . . . and how you always call me Sweetie, even though you say that you call everybody Sweetie. I love that you knew exactly what to get me for Christmas, without asking. And that you'd beat up bullies for me," Sheldon continues.

"I love how good you are at Halo 3 . . . and the way you sing Soft Kitty. I love the way you smell. I think a part of me has been in love with you since the day we met. And I know you think I'm a robot, and that I'm strange . . . And I know I don't possess the Alpha male body type that typically appeals to you. I realize that you'll probably never love me in return. But I . . ."

Penny pushes Sheldon's chair roughly into the back wall of office, catching him completely by surprise. Then, she straddles him, so that she's sitting on his lap. Finally, she wraps her arms around his neck, and kisses him, deeply and intensely. His eyes widen for a moment, as he gasps for breath. Then, he allows them to fall blissfully closed.

It takes a couple of minutes. But, eventually, he gathers the strength to push her away. "Please don't tease me again, Penny," Sheldon warns. "I can't handle it."

"Tease you?" Penny asks, as she gently strokes his face with her hand. "I'd never tease you, Sheldon. I broke up with Leonard this morning."

"You did?" Sheldon asks, his voice sounding surprisingly childlike.

"I did . . . because I love you too, Dr. Wackadoodle. You snuck up on me, Sheldon Cooper, with your 187 IQ, and your eidetic memory, and your crazy knocking . . . and all those ridiculous facts you store up in that brain of yours. Being with you . . . I don't know . . . It just feels like . . . home."

Sheldon breaks into an ear-to-ear grin, as he cups Penny's face with his hands. He then stares at her in wonder, for a few moments, before gently pressing his lips to hers. Penny moans softly, her hands deftly massaging the back of his neck, as the kiss deepens.

"So, what do we do now?" Sheldon whispers into Penny's neck.

Penny pulls back, so that she can look him in the eye. "Well, it's going to be really messy . . . with Leonard and Amy, Howard and Raj . . . even Bernadette. Not to mention the two of us. We're going to make each other crazy! And we're probably going to fight all the time! So, I'm constantly going to be calling your mother. But I'm willing to give it a try, if you are."

"Penny, are you asking me to engage in a Relationship Experiment with you?" Sheldon inquires.

"I'm asking you to be my boyfriend," Penny corrects.

Sheldon nods thoughtfully. "That sounds like a reasonable proposition. I accept," he replies.

Penny smiles, as she pulls Sheldon in for a hug. "Good answer," she says.

Suddenly, Sheldon's face becomes very serious. "Penny, you should know that I'm not ready to engage in coitus with you. I think I will be . . . one day. It's just that, right now, I . . ."

Penny runs her hand through Sheldon's hair. "I know, Sweetie. And it's OK. There's no rush. For now, I'll settle from some heavy makeout sessions, and a little light boob fondling."

Sheldon brightens. "Well, according to my digestion schedule, I don't need to use the restroom for another ten minutes. I'd be happy to fondle your boobs until then."

Penny crinkles her nose at the reference to Sheldon's much-too-often discussed bathroom schedule. "Oh honey," she says, as she closes the blinds in his office, and locks the door. "I have SO much to teach you . . ."