When their expedition to the arctic ended and they returned home, things didn't return to normal the way that Sheldon had expected. Leonard and Penny quickly entered into a romantic relationship and changed the dynamic that Sheldon held with both of them. Any time that Leonard or Penny showed any form of public affection it made Sheldon feel physically ill. Bile rose in his throat at the slightest touch shared between the two. Sheldon had gone so far as to ask Leonard to refrain from being affectionate with Penny in front of him in any capacity, but Leonard responded by telling him that it was crazy to ask him to not even touch his girlfriend. Sheldon responded to this refusal of his request by staying late at work, going over to Raj's apartment much more often than normal, and spending the majority of his time at home in his bedroom.

Despite the increased number of work hours, Sheldon found that he was less productive than he had ever been. One evening, he stood in his office working out a problem. His mind refused to focus on the equations on his white board and instead began musing on what Leonard and Penny might be doing at that moment. A wave of nausea hit him and he sat down at his desk. He had come up with a rough plan over the past couple of days, but had yet to do any research to determine its plausibility. He opened up the internet browser on his computer and began typing.

"I'm moving back to Texas." Sheldon announced to the group a few days later.

"Sheldon, what are you talking about?" Leonard asked from his chair at the edge of the living room.

"I have accepted a job at the University of Houston. The physics department is not quite to the calibre of that of CalTech, however it will allow me to be much closer to my family. As my MeeMaw is ill, it will give me more time to spend with her before she passes on."

Penny got up from her spot on the middle cushion of the couch and walked over to Sheldon, who was standing near the kitchen island. She looked up at him with sympathetic eyes, "Oh Sweetie, I didn't know your grandma was sick. I'm so sorry to hear that." She reached up and rubbed circles on his back.

Sheldon took a breath and it caught in his throat. After a moment he spoke softly, "thank you for your condolences Penny." He cast his eyes downward and took a sip of his tea.

It had taken Sheldon a while to realize that what had been afflicting him since he had returned home was not any type of illness. After much research and deliberation he came to the realization that the sick feelings he had been having were jealousy, pure and simple. He found himself wanting to be the one with his arms around Penny, and seeing Leonard in that position began to become more than Sheldon could handle. He was unaware of how these feelings developed; she had been with plenty of men in the past two years that she had lived across the hall, and none of them had made him feel this intense jealousy. He had known since the beginning that Leonard had had feelings for Penny, but the thought that they could ever be in a real relationship was not something he had deemed a possibility. Seeing them together made these jealous feelings so much more intense, however they never really left him and Sheldon deduced that the only way to return his life to the way it had been was to remove himself from the situation. His thoughts were clouded in a way that they never had been before, and Sheldon felt that it was his duty to science to keep his cognitive processes at an optimal level.

While Sheldon realized that he was jealous, he never took the time to think about the real reason for these feelings, only of how to make them go away.

Within the next couple of weeks Sheldon meticulously packed up all of his belongings and labelled them appropriately. With the help of his mother he had secured a small apartment within walking distance of the university. He shipped the boxes filled with his things to his new address, keeping only a few toiletries and items of clothing.

The morning of his departure he was alone in the apartment, Leonard already having left for work. The guys had thrown him a going away party the night before, but it had been subdued. Despite a few sarcastic comments about Sheldon's personality, the night had had a sombre tone. Sheldon stood in the middle of the living room, his small suitcase and carryon bag placed by the door, ready and waiting. There was a soft knock and then the door swung open to reveal Penny standing behind it, wearing her Cheesecake Factory uniform. Penny's shift that day started in the early afternoon so she was available to drive Sheldon to the airport to catch his late-morning flight.

"Ready Sweetie?"

Sheldon swallowed the lump in his throat and nodded. Penny picked up Sheldon's suitcase as Sheldon grabbed the carryon. He reached into his jacket pocket, pulling out his key for the apartment door and dropped it one last time into the bowl.

The drive to the airport was spent in near silence, neither of them knowing what to say. Penny stayed with Sheldon until it was time for him to go through security. They stood, facing each other, next to the barrier for the security line, Sheldon's carryon on the floor at his feet.

"Thank you for driving me to the airport, Penny."

Penny's eyes glistened as she looked up at him. "You're welcome, Sweetie."

Without any hesitation Sheldon took a step forward and wrapped his arms around Penny. Before Penny even knew what was happening, she was wrapped up tightly in his embrace. She leaned into him, palms flat against his chest, feeling the beat of his heart through the layers of his shirts. He squeezed her tighter and she tucked her head under his chin. After a moment that felt far too short, Sheldon let her go and bent down to pick up his bag. When Sheldon straightened he looked into Penny's face to see a too-large smile and eyes that were brimming with tears.

"Have a good flight!" she said, sounding much too chipper.

"Goodbye Penny. Take care."

"Bye Sheldon," she whispered at his back as he walked up to security. She watched him until he disappeared to the other side of the metal detector. Not once did he turn back to look for her.