After laundry had been washed, dried, folded, and put in their respective hampers, the duo made their way upstairs. Much to Penny's amazement, Sheldon didn't seemed bothered by the idle chit chat up the stairs. In fact, he kept it moving fairly well. As they reached the forth floor, Penny made her way to her door, a small smile on her face.

"Penny, the offer to join us for dinner remains. I hope you'll join us." His tone was sincere. Since she'd known him, she was happy to see his progression when it came to social settings, and showing emotion. He learned a little slower at times when it came to either, but was much better then he had been.

Smiling, she turned to him. "I know, sweetie, I'll be over in a few minutes. Let me just put this in my bedroom." With that, she opened her door and walked in, shutting it. Sheldon stared at her door a moment, thinking. Shaking his head, he opened the door to find the guys, plus Amy.

Nodding a greeting, he mechanically moved to his room to put his clothes away. It didn't take him long, not with his system. Everything went in it's exact place, neatly. Once he was finished, he joined the others. "Penny will be dining with us this evening. Her and I had a little chat, and I've convinced her to rejoin our little group. It seems that the Cheesecake Factory has been taking up all her time." He said simply.

"Well, I'm glad. I have much to discuss with her, and she hasn't been returning my texts." Amy said, slightly hurt. "It's like the worst heartbreak I could imagine. That beautiful goddess, ignoring me." The others looked at her, still not used to her displays of affection towards Penny. Even Sheldon looked at her funny.

As if on cue, Penny walked in, smiling. "Hey, guys." She waved, making her way to the couch. "Sorry I haven't been over. Work has been hell, but I'm off the next few days."

"You'll be at work on Tuesday, correct?" Sheldon asked, worried. Since he'd been forced to dine there, it had become routine. With that routine came with the expectaion that Penny, and no one else, serve him. She knew how he was about germs, how he preferred his food, and he trusted her. As the thought hit him, he shot out of his seat.

Penny stared at him. "Yes, sweetie, I'll be there Tuesday, don't worry." She hoped that would make him sit down, but was more confused when he made his way to his computer. The only time he did that was when he had something important to research for work. "Uh, Sheldon? I thought we were eating."

Turning slightly in his chair, he looked at his group of friends. It had changed, and it hadn't really occurred to him how much. Yes, he'd made new agreements, yes he'd made changes that he noticed. What he hadn't noticed was that out of them all, he trusted Penny the most. She cared about him, she stood up to him, she sang 'Soft Kitty' to him, and his mother loved her. Of course he trusted the others, but after the North Pole, that had taken a blow. "It occurs to me that there is much I need to learn about the social contruct of friendship." It wasn't really news to anyone, but they continued to stare. "Oh, for Heaven's sake. It seems that out of everyone here, I trust Penny the most. I have come to rely on her precence in our group." Amy shifted slightly. "She is the least like me, in every aspect, and yet, I enjoy her company. Now, why is that? I'm a genius, she's a college drop out. She prefers men that look like they belong in the Stone Age, and yet she hangs out with us." He continued, earing a glare from the blonde.

"Sheldon, don't you think that you would trust me most? Seeing as I am your girlfriend?" Amy asked, hopefully.

Shaking his head, Sheldon sighed. "Amy, no. You are the newest member of our group, and Penny has been there many times for me. Even when the others weren't." He shrugged. "And, in return, she has come to trust me. I know this from all we've been through."

Amy glanced to Penny, who was wishing she hadn't agreed to this. "He's, uh, right. He drove me to the emergency room when I fell even though he doesn't have a licence, and my check engine light bothered him. After we got home, he sang Soft Kitty to me." She smiled at the thought "It was weird, usually it's me singing to him."

"Soft Kitty? I don't recall having heard of this..." Amy repsonded, looking more hurt then before. The tension in the room was growing more and more by the minute.

Sighing, Sheldon turned all the way around. "Soft Kitty is a song my mother sang to me when I was sick. The first time I fell ill since Penny had been here, I taught it to her. She was kind enough to sing it to me while rubbing Vapor Rub on my chest." He explained. "And, when she fell in the shower, due to a lack of adhesive ducks, I drove her to the hospital. There she was drugged, and when we returned, she requested I sing it to her. Not only did I agree, once she pointed out that drugged and injured was a type of sick, we did so in a round." His mind drifted to that night. Of course he hadn't shown it, but he'd been worried. Not for her life, but for the amount of pain she was likely in.

"I see. Why have I never heard about this before?" Now it was Amy's turn to question Sheldon.

"Because, Amy, I have had no need for anyone to sing Soft Kitty to me since we've met. If I had, I'm sure had I not been able to reach Penny, I would have called you." He stated. His tone was matter-of-fact, as always. With that, he turned back to his computer, ignoring the others.

Leonard sighed and shook his head. Leaning over, he whispered to Amy. "Don't feel bad, he doesn't know what he's saying half the time." Which, of course, Amy knew to be true. It just didn't make it hurt any less that Sheldon preferred her bestie to her.