A/N: Set right after the tag scene of The Locomotive Manipulation. Everyone and their mother has already written about the SIK from a Shamy perspective, so I decided to write about it from Leonard and Penny's point of view. Ultimately, it turned more into a L/P fic, though. Oh, well. Also, it's the first time I'm writing in over two months, so please bear with me.

As always, I own nothing but the skin on my bones.

Sheldon hasn't been in his room for five minutes when the front door opens without a knock. Leonard knows who it is, of course, and he says "hey" says without looking up from his laptop, as he also knows Penny probably is out of milk again and simply sneaking in to steal Sheldon's. It's a surprise when she wraps her arms around his neck from behind, resting her cheek on the top of his head.

"I love you," she says, and Leonard blinks, wondering whether the world has come to an end. Between Sheldon kissing Amy and Penny voluntarily seeking him out to get romantic, it certainly feels that way. Taking his hands off his keyboard, he absent-mindedly reached out behind him, his fingertips grazing her shoulders.

"Penny?" he asks, and it's as if he said it all, as if the way her name slid between his lips was all she needed to giver herself the courage of her next words.

"I'm sorry," she says, and Leonard has an idea he knows where this is going. "It was crappy of me, to give you a half-eaten, free box of chocolates."

He shrugs. "It's the thought that counts," he says, and as much as the gift she gave him has bothered him earlier, he realises now that this is very true. Penny's without a job, at the moment – she was never going to give him an amazing present. Big, swooping romantic gestures are not even who she is, anyway.

"I was just on the phone with my dad," she says. "He's coming to visit next month and we'll go to the game together. Thank you."

Leonard smiles. "Always happy to make you happy."

Penny straightens up, taking her arms off him, and Leonard can turn around and look at her for the first time since she walked in. She's wearing an oversized Bambi tee-shirt and a pair of black shorts, her hair up in a bun, her face without any make up. She obviously was about to go to bed before she came over here.

"Do you want to sleep here, tonight?" he asks, and Penny shakes her head.

"Do you want to sleep at my place?" she asks instead, and Leonard nods, still smiling. "Good," she says, and then bends over to quickly kiss him on the mouth.

"Just let me tell Sheldon I won't be here." Penny nods and exits his apartment – although, really, they've basically been living together for a long time; his, hers... it's all been mixed together without any of them ever noticing it, really. This hallway that once stood between the two of them has become part of their home.

Leonard walks to Sheldon's door and knock twice.

"One moment, Amy," he hears Sheldon's voice say, and a few seconds later, Sheldon opens the door, dressed in his Sunday pyjamas. Leonard catches a glimpse of his laptop open on his bed, and he guesses Amy's face is on the screen right now, waiting for Sheldon to resume their Skype session.

There's a weird feeling in Leonard's gut at the thought of Sheldon and Amy talking, and he's not quite sure what it is.

"Yes?" his roommate says, and Leonard mentally shakes himself.

"I'm sleeping over at Penny's tonight."

"Alright," Sheldon says, and before Leonard has the time to say anything else, slams the door in his face.

Well that was a little rude, he thinks as he walks back into the living room, before grabbing his keys and heading out to Penny's. He lets himself in and sees her pour wine into two glasses.

"Hey," he says, and she smiles at him over her kitchen island. He sits on her couch, and ten seconds later, she's besides him, resting her head against his shoulder. He puts her arm around her, and for the next ten minutes, there's no sound but that of their breathings as they drink their glasses of wine.

When he finishes his drink, Leonard can't help but ask where she got that wine. It's very good, much better than the cheap bottles Penny usually buys.

"Sheldon dropped it here like half an hour ago. Told me it was a gift from Amy. She bought it on their week end or something."

Leonard suddenly smiles, remembering his best friend's confession. "Is that all he told you?" he asked.

"Yeah. Well, no, he also asked whether I was ever going to clean my apartment. Typical Sheldon."

He's not even looking at her, but Leonard knows she's rolling her eyes. "And did you speak to Amy?"

"Nah, not since they left. Which was weird, because she usually texts me every detail of her life as it happens."

Leonard almost doesn't tell her, because there's probably a reason why Amy didn't tell Penny. Perhaps this feels too intimate to share, perhaps it's face to face news, perhaps she doesn't trust Penny enough – how would he know? He and Amy aren't exactly close. Leonard almost doesn't tell her, until he realises the weird feeling in his guts, the one he had at Sheldon's door, is actually pride. His best friend is growing up, and Penny deserves to know, too. They've been acting as Sheldon's parents for far too long for her not to know.

"Sheldon kissed her," he says, and he feels Penny straighten up.

"No," is her only answer, and Leonard shrugs.

"That's what he told me."

Penny's face stays blank for a few seconds, until she properly starts freaking out.

"Oh my God!" she squeals, clapping her hands together. "I can't believe it! Our little Shelly suddenly hit puberty!"

And there it is again.

"I like that word," Leonard says, and Penny looks at him, incomprehension painted on her face. "Our," Leonard explains, and then he adds, "we."

There's a long silence between them, and Leonard suddenly worries he said the wrong thing. What if, all this time, he's been the only one thinking that they were basically sharing everything already? What if, for Penny, they're not a "we" but a "you and I"? What if, once more, he loves her more than she does him? Even if she says "I love you" back, now, Leonard figures you never really leave your old insecurities behind.

But then she smiles, and she says "Yeah. I like it too."

Leonard smiles back, leans in, and kisses her again.

A/N: Thank you for reading! If you liked it, please consider leaving a review! :)