A/N: I wrote this while I was stuck in a training all last week. Obviously, I wasn't paying attention. Oh yeah, I don't own CSI or anything related to them.

Stay

Sara Sidle slipped into the Harvard University auditorium quietly. The Physics major had seen a flyer for this seminar on Forensic Science posted near her dorm room. Though she had no interest in working with criminals, anything related to science tended to peak her interest.

"My name is Dr. Gil Grissom - Entomologist, Level III Crime Scene Investigator for the Las Vegas Metropolitan Police Department and your lecturer for the next several weeks." He said scanning the audience. "I'd like to keep things informal. Feel free to interrupt with questions and/or comments. Also, just let me know when you need a break. At the end of each daily session, I am free to speak with anyone who is still awake." That solicited a chuckle from the group. "Okay, let's begin."

Forty-five minutes into the lecture, Sara was completely enthralled. Forensic Science had sufficiently peaked her interest. She had never met anyone so knowledgeable and passionate about his work. It didn't hurt that he was absolutely gorgeous.

"Let's take a fifteen minute break." Grissom suggested after scanning the audience again to judge for alertness. It didn't bother him that most of the medical students were required to attend and therefore found his sessions to be boring. What kept him going were the few that showed genuine interest. If he could walk away at the seminar's end with one convert, then it was time well spent.

For example, the pretty brunette that sat in the rear of the class. Sidle, she had said. Her name was Sara Sidle. He knew she was really listening. Not only did she nod, smile and laugh in all of the right places, but her questions were intelligent and well thought out.

During the break, Sara made her way to the front of the room where the professor was reviewing his notes. "Excuse me, Dr. Grissom?" Sara spoke nervously.

Gil looked up from his notes, removed his glasses and smiled. "Ms. Sidle?"

"Yes, that's me." She answered breathlessly, pleased that he remembered her name.

"How can I help?"

"Uh. Your lecture so far has been very interesting, but I was wondering if you were going to have a slide presentation? I mean, I'm not trying to rush you or change your curriculum or anything…" she finished weakly, staring at her hands.

"Ms. Sidle-"

"Sara, please."

"Sara, I thought you were enjoying the lecture." He couldn't hide his disappointment.

"Yes, I am! You're great! I-uh, I mean the lecture is great."

"But…?" He prompted.

"But when you started talking about how the bugs can reveal and establish the time of death and blood splatter - I mean, I want to see the pictures, the case files. What type of experiments have you performed to back this up-?"

"Whoa! Sara, slow down. So, what you are saying is that I'm moving too slow?"

Sara smiled sheepishly.

That's when he knew. He had one.

Later that night in his furnished apartment, compliments of Harvard University, Grissom replayed the day's events. The lecture had been a wild success. Mainly, due to one Sara Sidle. After their brief talk during the break, he picked up the pace by altering his itinerary - something he rarely did. But the excitement he saw in Sara's eyes was catchy. By the end of the class, he had a record seventy-five percent class participation.

"Sara." He said her name out loud into his empty room. He liked the way her name sound on his tongue. It had been a long time since he gave a second glance to a woman. But there was something about Sara. She was beautiful, smart and had a wonderful gap toothed smile that made him feel things he hadn't felt in years. He leaned back in his chair and imagined what it would feel like to run his tongue along the small space between her teeth while his hands explored her round hips and breasts.

The telephone ringing interrupted his very un professor like thoughts.

"Grissom."

"Uh, hi. Um, Dr. Grissom - um-.."

Sara's mind drew a complete blank. His voice was incredibly sexy on the telephone.

"Sara?" At the lecture's end, Sara had more questions, thoughts and ideas, so Grissom had given her his telephone number with plans to continue their discussion. Who was he kidding? Grissom simply wanted to hear her throaty voice that made his insides vibrate.

"Sara?"

Right! Yes! She was Sara. She reminded herself.

"It's me."

"Sara, how are you?"

Uh?

"Sara, this conversation will go a lot more smoothly if you answer back."

She visibly relaxed when she heard the smile in his voice.

And so began an easy camaraderie and they became fast friends.

By the third week of class, Sara and Grissom were spending most of their free time together. It started off with long talks after sessions, then progressed to dinner and shared meals on the weekend. They talked about any and everything from forensics to their families.

They connected on an intellectual level immediately and neither was surprised when their attraction quickly moved to a sexual level. It started with personal space violations and innocent brushes against one another. Then there were shy touches and outright looks hunger. Both found it increasingly impossible to keep their hands off of one another.

Grissom knew he had long crossed the line of sanity. What was he doing in a relationship with his student? His much younger student? They had not consummated their relationship but at the rate they were going, it wouldn't be long. He was only human.

He couldn't help it; all of his logical and ethical reasoning went out of the door when he looked into her beautiful brown eyes or when she smiled that special smile reserved especially for him. He was risking everything, his career and reputation to be with Sara but when she was in his arms, he couldn't think of any other place he would rather be.

Sara stared at her reflection in the mirror. What was she doing? She'd fallen in love with her professor - she'd fallen in love with Grissom. Though she considered herself reasonably intelligent, she knew this was not the smartest thing she'd ever done, by far.

Even though they were careful, she knew that if any one found out, Grissom would be fired. She didn't care what happened to her, but his career was his life and she wouldn't purposefully do anything to jeopardize that.

But he was the one. In her heart, she knew that he would be the only man she would ever love. Gil Grissom had become her world and they hadn't even had sex! He was her first thought when she woke and her last when she closed her eyes to sleep. She dreamed of a life with him when he returned to Las Vegas. She never gave into childish fantasies before but she couldn't help dreaming of marrying Grissom and bearing his children. It's what she wanted more than anything in the world and when she looked into his beautiful blue eyes, she knew that he loved her too.

He was in love with her. The concept was foreign to him but there was no other was to describe the way he felt. The timing could not have been worse, however. His position as visiting professor would be over in six weeks. It was crazy. What would he do when he went back to Vegas? Pretend that he hadn't become involved with his student?

Maybe Sara would forget about him when he left. She'd finish school, probably be offered a wonderful position somewhere as a physicists and eventually marry and raise a family with someone closer to her own age. Speaking of which, their age difference had been the source of more of his already prematurely graying hair. He'd be forty soon. Time was a luxury that they both did not share. She said it didn't matter to her. She may think that now, but what about in ten years?

He downed the remainder of his scotch and dialed the phone with clumsy fingers.

"Willows."

"Hey, Cath. It's Grissom."

"What's going on, Gil? You partying alone?" She commented on his slightly slurred speech.

Grissom sighed deeply and then plunged in headfirst.

"Catherine, I'm in trouble."

"What's up? You need me there?"

Grissom smiled. Her reaction was not unexpected. He knew like he knew his own name that Catherine Willows was his true friend.

"It's nothing like that."

"Ookaaay. Spill it Gil, you're killing me here."

"There's this girl…" Grissom started speaking and didn't stop until he told Catherine everything.

It felt good to finally share his predicament with someone.

"Oh my God. Grissom, you're in love with her." Catherine said with plenty of emotion.

"I think so."

"I'm happy for you."

"But?"

"But, I see the problem."

As Grissom's tenure drew closer to an end, their passion was spiraling out of control.

"Sara wait." Grissom groaned one night at his apartment.

"Can't I stay? Please, I think I'll go crazy if I don't stay. I need you." Sara breathed into his neck.

"Sara." His said fighting for control. "We can't."

Sara began to weep. "I want to be with you so bad."

"I'm so sorry sweetheart. I should have never let it go this far." He whispered and held her close. It broke his heart to turn her away. He wasn't sure how many times he would be able to. He wasn't sure that he wanted to anymore.

"Grissom, I love you. I -I want to be with you."

He kissed away her tears, and then moved down to her lips.

"Sara, I…but…we- I can't." He struggled with the words.

"Don't you want to be with me?"

"Sara, I ache for you. But-"

"Don't." She placed a finger to his lips to silence him. "Just tonight. Love me, just for tonight?"

Grissom met her eyes and knew he would never have the strength to deny her anything - not even when everything he'd worked so hard for was at stake. He felt like he was standing on the ledge of a tall building. He sighed heavily, and then took the plunge. "Just tonight."

Sara woke the next morning in a cocoon of warmth. This is what it would have been like, she mused. This is what it would have been like to wake up next to him every morning for the rest of her life. But it would never happen again. He had made his decision. He didn't want her that way.

She almost sobbed out loud as all of her fantasies of a future life with Grissom crumbled. After last night, they would continue as friends and in a few weeks, he would return to Las Vegas and she would return to her desolate life.

Grissom stirred in his sleep as she studied his relaxed face openly. Sara was sure he had no idea how beautiful he was. Planting small kisses on his cheeks, she could tell from the change in his breathing that he was waking.

"Morning." Grissom murmured.

"Morning." She returned softly, meeting her eyes. "I should go."

"Sara, I've been thinking…"

Sara braced herself for the rejection she knew was coming. But she'd been prepared for this; this was how it had to be. She wouldn't have traded one second of their time together. She had no regrets.

"I know, Grissom. And I understand. I'll go now."

"Sara, wait." He reached to stop her progress from the bed. "Stay."

"Grissom, it'll be easier, no, it would be better for me to go now before-."

"Sara, I love you."

"I love you too, but that doesn't solve anything."

"I know, but it's a start. I'm going to apply for a permanent teaching position here."

"What? Really? What about your job in Las Vegas?"

"I- I can't imagine - I can't leave you. Class is almost over, you'll no longer be my student we could um…get married…I-I mean, if you wanted to…only if you wanted to."

Sara sat up stunned. He was willing to give up everything to be with her?

"Yes, I want to."

They agreed that Sara would keep her apartment until after the semester was finished but that didn't stop them from spending every available moment together. Grissom contacted his mother that same night, and as expected, she was thrilled with the news. Sara's parents, however, were skeptical of their daughter's choice. Her mother felt that she was too young and that Grissom was too old for her. Sara quickly dispelled any further arguments as her own father was ten years older than her mother.

Everything was perfect. For just a little while, everything was fine.

The night Grissom came home to tell Sara his good news - he'd been offered a position at the University, he returned home to an empty apartment. Sara was gone. All of her belongings had been removed from the premises. Grissom was stunned.

She'd been paying too much attention in class apparently, as she left no physical evidence of her previous existence in the apartment. She did, however, leave a note. A note that explained that she changed her mind, that she was indeed too young to rush into marriage.

It was like a bad movie Grissom thought as he fell onto the couch, clutching her note in his hands. He knew that she had been tense and withdrawn lately, but he had contributed it to the stress of finals and hiding their relationship. Never, did he think that she was unhappy. She gave no sign. There was no indication. They loved each other.

The final lines of her note devastated Grissom. Sara wrote that she had met someone. Someone, she could have a more realistic future with. Her words screamed "someone my own age."

She was gone

Grissom returned to Las Vegas a changed man. There was no way he could stay in Boston and see her with another man. Instead, he poured himself into his work, vowing that no one would never again have the opportunity to hurt him that way. Upon his return, he was offered the position of night shift supervisor, which he gladly accepted. More work meant less time at home to think. He eventually shared the story with Catherine only with the promise that they would never discuss it again and they never did.

Eight years later…

Las Vegas Crime Lab…

Grissom walked into the conference room and took a seat at the head of the table.

"Let's review what we have so far on the Mather's case."

Grissom nodded his head in Warrick Brown's direction, and he began. Nick Stokes, the newest CSI to the team eagerly jumped with his information while Catherine wrapped up everything they had to offer last.

"Good. Now let's go back to the scene with fresh eyes. Seems, we'll finally be getting some help…"

She could hear his voice from the hall. Following the directions to the room as instructed, she stepped into the small room and spotted Grissom immediately.

"Excuse me." She said clearing her throat and getting everyone's attention.

She couldn't have missed Grissom's scowl if she were blind.

Grissom's mouth fell open, and then he quickly recovered. "What are you doing here?" He demanded harshly.

"I-uh. I'm the new CSI." She finished defiantly.

Nick, Warrick and Catherine were shocked at Grissom's open hostility to the stranger.

"Not for long!" Grissom spat out, jumping up from his chair, sending his chair crashing to the floor.

"Whoa! Gil? What's going on here?" Catherine questioned with a hand on his arm.

"There's been a mistake." He said gesturing towards the stranger.

"There hasn't been a mistake. I'm the new CSI, so live with it." Sara spewed hotly. No way was she going to let him see how much he affected her.

"Okay, so who are you?" Warrick questioned.

"Sara Sidle, CSI Level II from San Francisco." She said extending a hand.

Catherine almost fell out of her chair when she introduced herself!

"You're Sara Sidle?" She said incredulously.

"I am."