AN:. My first attempt at a BBT Story. Canon up to the end of season 4 and then AU from there. There will be three chapters and possiblly an epilogue.

All recognizeable characters are the property of Warner Brothers and Chuck Lorrie. I just borrowed them for a while.

One: The Beginning of the End.

"You're in my spot." Sheldon whines, as he pokes his roommate that he discovers sound asleep on the sofa. "Why are you out here? You have a perfectly adequate bed in your room."

Leonard looks up at his seemingly always upset roommate with bleary eyes, moving his glasses back into place. "I came back late... somebody was in my room, so I crashed out here." He offers as he moves into a sitting position at the opposite end of the sofa.

"Who was in your room? Our roommate agreement clearly prohibits unauthorized guests." Sheldon comments in his typical pompous, matter of fact manner.

"How should I know? I was supposed to spend the night at Raj's place Skyping with Pria." Leonard counters, hoping to not have to explain the previous evening's events to Sheldon, who wouldn't understand anyway.

Just as he finishes his remark, a visibly disheveled Penny emerges from his room. It was obvious that she was suffering from a world class hangover. Before she reaches the common area between the living room and the kitchen, another person appears behind her, partially dressed and wrapped in a blanket.

The look of absolute shock on Leonard's face was contrasted by the puzzled one on his roommate. Penny sees the look on his face and tries to offer an embarrassed smile before remarking. "It's not what it looks like." She nearly sprints to the door quickly exiting, leaving Raj standing there, looking equally worse for the wear.

Clearly puzzled, Sheldon turns to Leonard and inquires. "What does it look like?"

Raj gives Leonard an embarrassed look and is out the door leaving the two standing there. Without a word, Leonard leaves his roommate standing there, uneaten bowl of cereal still in hand and walks to his bedroom. Ten minutes later, he reappears, suitcase behind him as Sheldon begins another rant about how the interruption to his morning routine ruined his breakfast.

Leonard stops at the door and sighs, giving the room a last look before remarking. "I'll send someone to gather up what's left of my belongings as soon as I figure out where I'm going. Goodbye Sheldon. I'd like to say it's been a pleasure, but that would be a lie."

Leonard is nearly out the door when Sheldon sprints from his seat to his desk, extracting a bundle of papers from his drawer and waves them before his soon to be former roommate. "You can't move out! Our roommate agreement clearly states that only I can make such decisions."

"So sue me." Leonard replies emotionlessly, as he leaves the place that had been his home for the last five years.

Nearly a week passes before Penny comes upon the two movers that were taking the last of Leonard's furniture from what used to be his apartment. She had been so ashamed of how he had seen her that she had avoided all contact with him or any of his friends. Now that she thought about it, there had been no attempts from either Bernadette or Amy to call her either.

It was after her shift at the Cheesecake Factory that Howard answered her call to Bernadette's phone and she learns of Leonard's abrupt departure. Howard was diplomatic as possible trying to explain that no one had seen or heard from him since the morning she saw him and that everyone was clueless as to why. Penny knew exactly why and so did everyone else.

Within a month, the once tight knit bunch had fragmented into nothing. They never realized that Leonard was the glue that held the group together. He had been the reason that everyone tolerated Sheldon's condescending, dismissive, and downright rude treatment and without him there, the good doctor was left to fend for himself. Even Amy had reached her limit, deciding to end things with him after her repeated attempts to assume the role as his roommate were summarily dismissed as stupid. This in spite of the fact that she had become the sole provider of transportation for him and the lone person that would listen to his rants regarding whatever happened to upset him at that moment.

Penny had ended all contact with Sheldon a week earlier after one of his tirades about Leonard leaving the way that he did as she drove him to the train store, actually a toy store that sold model trains.

Howard and Raj barely spoke now. Howard may have been a sleaze around Penny in the past, but once she and Leonard began dating, the Bro code applied. Raj had clearly violated the code by ending up in bed with Penny. The fact that it was her former boyfriend's bed only made the offense worse.

Attempts to find out Leonard's whereabouts were fruitless. He had changed cellphone carriers and the University could not give out any information. Penny had even tried contacting his mother, who had no idea that he had left the city and attributed his actions to his personal shortcomings.

Eighteen Months Later:

Howard Wolowitz's flight from Houston pulled into the gate. It was his first time back in Los Angeles in over three months and he was eager to see his wife after being away. Wearing his NASA windbreaker and ball cap, he strides confidently to the baggage claim area where he sees the handmade sign, 'Welcome Home Astronaut Wolowitz' being held by Bernadette and Raj. The two had mended fences and Raj had served as his best man. Amy had been Bernie's maid of honor at the small ceremony attended by their families.

Penny had been invited but did not attend. Somehow Leonard managed to send a gift and congratulated the couple on their nuptials. He also congratulated Howard on his then upcoming trip aboard the International Space Station, saying how proud he was of his friend. That was as close as anyone had come to having contact with Leonard since his departure.

Sheldon had been fired by Cal Tech nearly a year earlier after he, in his usual condescending manner proceeded to ridicule some of the school's biggest donors at a fundraiser for the physics department. His attitude towards his fellow scientists, combined with the lack of any type of breakthrough, made the decision to dismiss him an easy one. In typical Sheldon Cooper fashion, he told them how they were now on his enemies list and would rue the day they let his genius go.

With no job and no real prospects, thanks to his arrogant attitude, Sheldon returned to Texas and took his old room at his mother's house. Six months later, he was teaching physics at a small college in his hometown and working on his theories at night in his room. Between his mother and me-maw, they managed to keep him in control well enough to get by. Barely.

Amy had met, and was engaged to a neuroscientist she had met at a conference not long after she pulled the plug on the strained relationship she had with Sheldon. He was the antithesis of Sheldon, empathetic, considerate, and humble, three adjectives that would never be used to describe him. Her work with regeneration of brain cells was garnering a fair amount of attention for the school and large research grants, making her a rising star at the school.

Penny still worked at the Cheesecake Factory and spent her spare time auditioning for roles she knew she would never get. She moved from her apartment after her blowup with Sheldon, taking an even smaller place that was closer to work. She talked to Bernadette on birthdays and holidays, but the conversations were never about 'him'.

She had even tried dating Zak again after she learned that he was wealthy, but not even his money could make her forget how truly clueless he was. It seemed that every man she dated came up 'short' when compared to him. They were either too self centered, or too arrogant, or some other reason they didn't measure up to her idealized memory of him. Far too many nights were now spent sitting alone with a bottle of wine in her tiny apartment ridiculing the choices she made.

At first, she wanted to blame her entire mess on Wil Wheaton, as it was his goading that led to her finally breaking up with Leonard. Unfortunately, the truth was she had already made the decision to end things with him and all Wil did was provide her an opportunity. She was used to dating the big, muscular, handsome guys that the other women would see and envy her being with. Guys like Kurt.

But then along comes this short, bespectacled, nerd that looks at her as if she hung the stars in the sky. He was intelligent, kind, generous and treated her like a goddess. It took nearly two years, but he finally managed to worm his way past her defenses and into her heart. And for a while it was enough. He was enough. Hell, even her father liked him.

While she had been content with the way their relationship was at that time, Leonard was not and knew that unless thing's progressed, they would fail. In the end he was right, her fear of moving forward brought all her doubts to the surface and she decided to end things with him. Penny had been sure that if she changed her mind, he would be there, waiting.

By the time she realized her mistake, karma had the last laugh, as Leonard had started dating Raj's sister. Pria was an International lawyer, intelligent and successful, three things she was not. And beautiful. At first, Penny was sure that it wouldn't last, that he would come to his senses and see that she was available. In spite of the fact that she had never mentioned wanting to get back together with him.

Instead, she played the role of best friend, supporting his relationship with Pria, while waiting for it to fail. Leonard was clueless about it all and truly thought that she was simply being a good friend. Pria was not so naive and knew that her rival was waiting for her chance to reclaim him. This only made him more desirable to her.

Then came the promotion and her return to India. At first, Leonard convinces her that they could make a long distance relationship work somehow, but she knows it will fail. And it does in a spectacular manner when she informs Leonard that she has started seeing her old boyfriend.

While he was having his affections rejected for the second time in year, Penny was sitting in his apartment bemoaning her love life while trying to consume enough alcohol to numb the pain. Raj matches her drink for drink complaining about his nonexistent love life as well.

What happened after that was still unclear to her even now. The only thing she knew for sure was she awoke in Leonard's bed, nude, and with the worst hangover ever. Then she turns to look at the man asleep beside her and finds that it wasn't Leonard. Fragments of the previous evening's events come rushing back, none of them making any sense.

She pokes Raj awake, hoping that he can shed some light on how the two of them ended up together naked, and in her former boyfriend's bed, but of course his mutism is back, rendering him speechless. "Really? After whatever happened between us last night? You still can't speak?" Penny sarcastically comments as he gives her a timid smile in response that only makes things worse.

She hears Sheldon's whiny rant coming from the living room and nearly falls out of the bed trying to locate her clothes that are scattered everywhere, praying that she can make an exit before Leonard sees her like this. However, luck was not on her side as she nearly sprints from his bedroom half dressed and sees Sheldon and Leonard standing by the sofa.

If she lived to be a hundred, she would never forget the look of shock on his face seeing her leaving his room. That look was short lived as Raj appears behind her, wrapped in one of his blankets, clearly naked beneath. It was now a look of betrayal that was only made worse by her "It's not what it looks like" comment.

It would be her last memory of the only man that truly loved her.