"Sheldon," Amy started, "I've been thinking about what happened during our date night last month."

"They remade your burger without avocado on it once you explained that you're allergic. I think we should give them another try. Aside from the avocado, it was a good meal for a restaurant I've never been to before. We just need to remind them how important it is that your meal not come in contact with avocado," stated Sheldon as he continued to work on the equation on the board in front of him. Amy had stopped by his office unexpectedly in an attempt to talk to her boyfriend.

Amy knew trying to talk to him at work could be a problem, but she was unsure when they would have time alone together. "That's not what I'm talking about, Sheldon. This is serious. I know you're busy, but can you please take a break for a few minutes?"

Recapping the marker in his hand, Sheldon turned around and crossed his arms over his chest. "Okay. What do you want to talk about?"

"I've been thinking about the conversation we had at your apartment."

"Oh, that. What about it?" Sheldon asked, trying to sound like he hadn't stopped thinking about that conversation the past few weeks, either.

Amy took a deep breath before speaking. "I checked with the clinic I used and it turns out they have multiple locations. Once a donation is in their system, it can be selected by someone at any of their clinics. They have a location in Pasadena, on Green Street."

Knowing what this meant, Sheldon needed to hear Amy say it. "What does that mean?"

"Unless there are multiple clinics on Green Street, which there aren't according to Google Maps, you made a donation at the same clinic I used to have Max. There is a possibility you are the donor I selected," explained Amy, watching Sheldon's face for signs of panic as she continued.

"There was always a possibility of that being the case, now we know the probability of it being true is much higher than what we originally thought," pointed out Sheldon.

"I would like to find out for sure so we don't have this unknown thing hanging out there," Amy's comment was met with silence, which she wasn't surprised by. "We don't have to talk about this more right now, but I would like to talk about it sooner rather than later."

"I haven't heard from Sheldon in a while. You think he's okay?" Leonard questioned, getting up from the couch and crossing the room to his desk. "I'm gonna see where he is."

"How?" Penny suddenly seemed interested in Leonard's quest to find his roommate.

Typing on his laptop, Leonard explained, "I know his password so I can track his phone. That's weird. He's at the train station. I don't like this. Let's go get him."

Penny and Leonard easily found Sheldon when they arrived at the train station, much to his dismay. "We were worried about you," shared Penny.

"Don't be melodramatic," Sheldon rolled his eyes. "I'm just getting on a train and leaving forever."

"I know there's a lot of stuff going on, but it's nothing we can't work out," Leonard tried to get Sheldon to come home with him.

Staying firmly planted in his seat on the bench, Sheldon refused. "I've reached my breaking point. I need to leave. It doesn't matter where I'm going. I am overwhelmed. Everything is changing and it's simply too much. You two are engaged and the comic book store burned down. Then there's the whole Amy and Max situation. I need to get away and think."

Amy paced apartment 4A while on the phone with Sheldon. She came over the next morning after Penny told her Sheldon had left. Max was watching his mom from where he sat at the kitchen island with the snack Penny made for him. "Okay, Sheldon. Thanks for checking in. Talk to you tomorrow? Okay, bye."

"We really think this is for the best," Penny stated as Amy picked up a pillow and started to attack Leonard with it. She finally pulled the pillow away from Amy. "Hey, why don't we go across the hall and talk?"

Nodding in agreement, Leonard practically pushed the women out the door. "Go. Max and I will be fine here, right, Max?"

Penny waited a few minutes after getting Amy across the hall before saying anything. "Sheldon said something when Leonard and I saw him at the train station last night that doesn't make much sense. He said there's the whole Amy and Max situation. What was he talking about? Did something happen between the two of you? Or between him and Max?"

"I told Sheldon I want to find out who Max's donor is and he pretty much shut down after that."

"He's known for years that this would happen eventually, didn't he? Although, I thought you were going to wait until Max was old enough to decide for himself? What changed?"

"When Sheldon's mom visited before Thanksgiving, he invited me to join them for dinner. I couldn't find someone to watch Max last minute after my dad's car died, so I brought him with us. At one point, Max asked Sheldon to take him to the bathroom. That was when Mary commented how much Max reminds her of Sheldon when he was that age and that if she didn't know better, she would think Max was his son," shared Amy.

Penny paused to think for a moment before replying, "I could see that. They are pretty similar and kinda look alike. How would a comment his mom made six months ago cause him to freak out now?"

"I only told him she said that a few weeks ago. When I told Sheldon, he told me he once donated sperm and asked me where the clinic was I went to. I used a place in Glendale; he went somewhere here in Pasadena," Amy explained. "We dropped the conversation that night, but I kept thinking about it, so I did a little research. It turns out that the clinic I went to has multiple locations, including the one Sheldon used."

"That was the day I moved into the building. Sheldon commented that day about how they masturbated for money," reminisced Penny. "I asked Leonard about it when we started dating. He said they didn't go through with it, but it sounds like Sheldon went back by himself and didn't tell Leonard."

Amy knew she had to tell the woman she considered her best friend the rest of why Sheldon freaked out and left, but was worried about it become a topic of gossip amongst their friend group. "I need you to promise to keep this between us if I tell you why he really left," she paused, waiting for Penny to agree. "The timing of Sheldon's donation and when I was looking at donors lines up. There's a possibility that he could be Max's donor. I told him I wanted to find out for sure so we don't have this thing hanging out there, both of us constantly thinking about, but not talking about, and that's when he shut down."

"Oh, sweetie. When he said the Amy and Max situation, that is not what I was expecting it to be. Aside from attacking Leonard a little while ago, how are you doing with all this?" Penny hugged her friend.

"Max heard me crying last night and crawled into bed with me. He wanted to know why I was crying. I told him that Sheldon went away for a little while and that I'm going to miss him. That led to Max crying because he didn't understand why Sheldon would leave like that and not tell him goodbye," Amy said between sniffles, trying to hold back tears. "I hope Sheldon isn't gone for too long. He promised Max that we would all go to Disneyland this summer. I'll take Max by myself, but it won't be the same without Sheldon."

Thanks again for the reviews. I love reading them!