Disclaimer: Characters contained within do not belong to me.

Author's Notes: I hope this story brings a bigger smile to your face than the last one. Thank you so much for the kind reviews on that one, and for stopping by for this one.

I can't thank Mingsmommy enough for her beta-tasticness, not to mention her friendship;)

The Ascent of Man

by Kristen Elizabeth

It is not the strongest of the species that survives, nor the most intelligent, but the one most responsive to change. – Charles Darwin

October 16th

Grissom knew she was gone from the moment he entered the townhouse.

It was the little things. Her shoes no longer lay just inside the door. Her jacket wasn't draped over the railing. Hank was whining, like it had been a few hours since he'd been let out. Her scent, that wonderfully earthy, exotically spicy smell that always spoke of Sara, had disappeared.

After two weeks of bliss, warmth and life had left, turning his home back into a house.

There was no note on the counter or stuck to the fridge. The only message on the answering machine was from Catherine, asking him if he was planning on interviewing any of Ecklie's candidates for the open spot on the graveyard shift. There wasn't even a missed call on his cell phone. She'd simply packed up and vanished. Again.

After taking Hank out to pee, Grissom set about readjusting himself to a world without Sara. He dumped what was left of her soy milk down the kitchen sink. He cooked the last of her meatless hotdogs for dinner. He wrote out a new grocery list, drawing double lines under "ground beef" and "chicken breasts." He put on Ravel's Bolero as loud as he could without drawing neighbor complaints.

It was only in the shower as the water slowly turned from hot to cold that the ache in his chest spread to the rest of his body. Holding onto the slick tiles for support, Grissom fought to keep breathing. He had already survived this, he told himself over and over. He could survive it again.

He stayed in the shower much longer than necessary, like the water could wash away his loss. Not that it ever did. By the time he emerged, his CD player had changed discs and the strains of Beethoven's Moonlight Sonata echoed throughout the house.

It was one of Sara's favorites and always reminded him of her. Dark and haunted, but delicate and beautiful at the same time. Even after he'd turned the music off, his chest still felt heavy. He was old and tired. No wonder she'd left him twice.

Hank was lying on the floor next to the bed when Grissom returned from the living room. The dog's chin rested on his paws; his ears perked up a bit upon his master's entrance, but he didn't lift his head. Clearly, Grissom wasn't the only male in the house affected by Sara's departure.

After Grissom traded his towel for a pair of striped pajama bottoms and a T-shirt from the San Diego Zoo, he pulled down the covers on his side of the bed, doing his absolute best to avoid touching the far side. Sara's side.

She had changed the sheets before she left. All he smelled was detergent. Not the sweet scent of her hair, not the leftover musk of their lovemaking.

His book was lying on the nightstand. When he picked it up, an envelope and a folded sheet of paper fell out onto his lap. He stared at both for a long moment, silently debating the merits of reading whatever Sara had left behind versus ignoring them to avoid any further heartache.

In the end, curiosity won out. The envelope was sealed and on the front, in her hurried scrawl, she'd written, "Read the note first, Gil." His mouth twisted into a reluctant smile. After slipping on his reading glasses, he unfolded Sara's letter.

Gil,

I don't expect you to forgive me for this for a second time, but I hope you know me well enough to know how hard it is to walk away from you. I would give anything to be in bed with you right now. It's where I go when I dream. Your bed. Your arms.

But my place isn't in Las Vegas anymore. I can't stay any longer. It's too hard. There are new ghosts here and I'm still not free of the old ones. I have to move on. And as much as I want to be with you, until the day you're ready, willing and able to go with me, we'll find ourselves on different paths.

However, paths can always cross.

I love you.

Sara

There was a postscript at the bottom of the page.

If you can forgive me, open the envelope no later than January 14, 2009.

Setting the letter aside, Grissom picked up the envelope. It was thick, like it held far more than just another note. He turned it over, prepared to rip into it, but he stopped at the last second.

Glancing over at the empty side of the bed, he frowned. Suddenly, inexplicably, he felt his pulse rising. Anger was like a tonic, magically erasing the emptiness, replacing it with righteous indignation.

How dare she deliver an ultimatum? She was the one doing all of the leaving, and yet she had the audacity to leave their fate to him? Leave Las Vegas or lose her. It was far too simple of a choice for their complicated relationship. And Sara was a fool if she thought he would be pressured into dropping the career he'd spent a lifetime building to chase after a woman who'd abandoned him not once, but twice.

Grissom yanked the nightstand drawer open and buried the envelope and letter under a pile of old journals, magazines and finished crossword puzzles. He slammed it shut, tossed his glasses aside, turned the light off, and closed his eyes.

Willpower was never to be underestimated. Sara's face never appeared in his dreams. It would be a long time before he would dream about her again.

January 4th

"Hey, Grissom?"

Greg's voice broke through the fog around Grissom's mind. Blinking, he looked up from the report in his hand. Despite having been staring at the autopsy results for what seemed like hours, he hadn't read a single world.

Although Grissom didn't bid him, Greg entered the office. "We're heading out. Riley says she knows a great place for breakfast. Thought we'd try something new. You up for it?"

He cleared his throat, but his voice still came out hoarse and tired. "No. Thank you."

Greg lingered at the door. "Are you okay, boss?" He lifted his shoulder. "We're all kind of worried about you."

"Well. Kind of don't." Grissom turned a page and adjusted his glasses. "Goodbye Greg."

Although Greg was no longer the youngest member of his team, at times it still felt like he was. Instead of leaving like others might have, Greg hung in the doorway.

"I got an email from Sara at Christmas." Grissom frowned down at the autopsy report and said nothing. "She asked about you."

Glancing up, Grissom fixed his glare on Greg. "Have a good day, Greg." There was no congeniality in his words. It was a clear command to leave or suffer the consequences.

It also wasn't the first time a well-meaning soul had been ordered out of Grissom's office in the past two months.

Greg sighed. "Yeah, okay. You too." As he walked away, he muttered, "Enjoy your fortress of solitude."

When he was gone, Grissom took off his glasses and rubbed his eyes. Every single part of his body felt heavy from exhaustion. It was getting harder and harder to show up night after night, keeping up appearances, doing his job knowing the whole time that he'd have to return home to an empty townhouse when the day was done.

It was getting harder to deal with his co-workers. They were too young, too full of energy and eagerness. Anything and everything was possible for them, all doors were open, while all he saw were doors closing behind him.

On his way out of the lab twenty minutes later, Grissom passed by the reception desk where Judy and another receptionist were working together to remove the last of the holiday decorations. The season was officially over. He'd lived through another Christmas and New Year's alone. The key, he'd discovered, was double shifts and single-malt whiskey.

Halfway to his car, his phone rang. He recognized the number, although he'd never assigned a name to go with it. It took him all the way to four rings to decide against answering it. Whatever Heather wanted at five a.m. couldn't possibly be a good thing for either of them.

And after the close call they'd recently had, Grissom had no intention of putting himself in an empty house with her again, especially not while his emotions were still so raw. And definitely not if she insisted on wearing nothing but La Perla while he was there.

He was still trying to forgive himself for his moment of weakness, the few seconds in which he'd actually considered her unspoken offer to seek comfort and companionship in her bed. As desperate as he was for human contact, he would never find true happiness in Heather's arms.

After three calls, each of which he let go to voicemail, Heather stopped calling.

The early morning air was too chilly to allow him to take Hank out for his usual walk after picking him up from the sitter's. Grissom gave him five minutes to do his business in the front yard before hustling him inside.

One hot shower and a cup of decaffeinated coffee later, Grissom slipped between cold sheets. Outside, the sun was rising, but with his blinds pulled, only the barest hint of light illuminated the bedroom. It was fitting. The rest of the world lived in brightness, while he drowned in the dark.

It didn't take long for fatigue to overwhelm him. He slipped into the deepest slumber, the sort where the mind is incapable of distinguishing dreams from reality.

And in his dreams, for the first time since she'd left him, Sara appeared.

She stood before him like an exquisitely carved statue, beautiful and pale, but stationary, immobile. Unable to go to him. Unable to do anything but watch him with sad eyes.

He found himself reaching for her, straining his arms to touch her. But before he could, he woke with her name on his lips.

"Sara!"

At the foot of the bed, Hank woke with a start. He barked once, a woofing warning that made Grissom sit up and fumble for the light. A quick glance to the left told him everything he needed to know.

Her side of the bed was empty. It had just been a dream. She wasn't with him. She never would be again. Not while he was here. He would always be alone, save for Hank who did his best, but could never completely fill the void she'd left behind.

Maybe someday the isolation would be too much to bear. Heather would call and he wouldn't be strong enough not to answer. Was a moment of release fueled by the desperation to escape the loneliness worth the lifetime of guilt that would follow?

Grissom rubbed the base of his throat to keep breathing. Was he living a life at all? Or was he merely existing, walking through every minute of every hour of every day? What did it all mean…what was the point if there was no one to share it with?

It was too late to regret that he'd allowed his happiness to become dependent on one woman. He'd made that choice a long time ago, the first time he kissed her and learned what he'd been missing for so many years. Sara was what he wanted. What he needed. There was no substitution for her, not work, not friends, and certainly not former dominatrixes.

And nothing was going to bring light to his darkness until he was with her again.

Turning his head, Grissom looked down at the nightstand. Before he even completely made up his mind, he found himself opening the drawer and digging through the organized chaos until he found what he'd buried there months earlier.

He read the letter again, concentrating on the postscript. January 14th. He wasn't too late.

With shaking hands, he tore into the envelope she'd left behind and pulled out a thick ream of printed pages. Without his reading glasses, he squinted at them, reading each tiny word slowly and carefully. When he was done, he looked up and swallowed several times.

It was the fourth of January. According to the printed plane ticket in his hand, he had a seat on a flight to Quito, Ecuador on the 28th. From there, he had another ticket to San Cristobal where he could, if he so desired, join Sara for a cruise of the Galapagos Islands.

His mind raced. Was it even a possibility? Was he needed here, really and truly needed, not just as a dusty figurehead, but as an active leader?

No. The team didn't need him. They were beyond him. Catherine would guide them when and if they needed guidance. Nick would remain the strength, Greg the heart, Riley the fresh blood. Maybe it wasn't fair to leave them after the loss of both Sara and Warrick, but they'd proven their resilience already. They would be just fine.

Life had to move on because nothing could stay the same forever. Not without becoming stagnant. Sara had known that. Now, it was her turn to teach him.

Suddenly, he felt as if he'd never been tired at all. Throwing off the covers, and worrying Hank in the process, Grissom went for his cell phone.

"Catherine?" he said after receiving her very sleepy and very grumpy greeting. "It's time."

Grissom surprised himself by actually sleeping on the flight from Las Vegas to Quito. After three weeks of making arrangements for everything from his job to his house to his dog, he was only able to rest once his plane was in the air and he was on his way to Sara.

From above, the Pacific Ocean looked more brilliantly blue than he'd ever seen it before. Everything, in fact, seemed more colorful since he'd made this choice. The world was alive, brighter than ever, and all those doors he'd thought were closed were suddenly open again

She had planned everything down to the very last detail, because she was Sara and she didn't do anything half-heartedly. The only thing she hadn't counted on was a flight delay. Although he landed in plenty of time to catch the connection to San Cristobal, the plane was delayed. And all he could do was sit in the Ecuadorian airport, across from a younger couple who were clearly on their honeymoon from the way they couldn't keep their hands off of each other, and count the minutes.

Unless the plane left soon, there wouldn't be enough time to reach the island and meet the cruise ship before it left. The idea of Sara waiting on the dock, believing he hadn't come, that he hadn't forgiven her, didn't want to be with her, gnawed at his insides. He must have looked as anxious as he felt because the honeymooning couple stopped kissing for a moment and looked over at him.

"Hey, mister," the young man addressed him. "If you need it, we've got Dramamine."

"Always puts me right out," the girl said, snuggling closer to her partner. "Makes flying a lot easier."

Grissom forced a smile. "Thanks. I'm actually more worried about making the flight than living through it." He looked down at his watch for the five hundredth time. "Ship leaves at sundown," he murmured out loud.

"You're taking a cruise, too? Alone?" The girl frowned, like this was a completely foreign and unhappy notion.

His fake smile faltered. "Hopefully not."

As his Spanish was limited, he didn't pay much attention to the announcement on the airport speakers until it was replayed in English.

Their flight had arrived and they would be boarding soon. Relief made his knees feel weak. He was going to make it.

From the tiny airport on the equally tiny island of San Cristobal, Grissom, the honeymooners and two other couples took a van to the docks. The cruise ship was unmistakable even from a distance, a looming silhouette against the blinding orange and reds of the setting sun.

As soon as the van came to a stop, Grissom was the first one out. A porter was on hand to unload their luggage and take it to the ship, so his one and only concern was Sara.

The docks bustled with activity in preparation for the ship's departure, but there weren't many passengers still waiting to board. It wasn't difficult to locate the lone woman standing at the rope railing, looking out over the ocean.

With his heart somewhere in the vicinity of his throat, he came up behind her.

"So," Grissom began. When she turned her head and he caught sight of her, he smiled, truly, genuinely. "Our paths cross."

Sara's cheeks shone in the dying light. "You came," she whispered.

Reaching out and cupping her face in his hand, Grissom wiped her cheek clean with his thumb. "I couldn't stay away." She opened her eyes and looked at him through wet lashes. "I love you, Sara."

After a deep breath, Sara took a step back, lowering her gaze. At that exact moment, a strong breeze swept over them, molding Sara's peasant blouse to her very gently rounded stomach. She put a hand to the unmistakable swell. "I had no idea when I left." The wind carried her voice away; he could barely hear her. "I couldn't have."

At a complete loss for words, all he could do was stare at her belly until the gust died down and her shirt hung loose, concealing her secret once again.

Grissom blinked. "A baby?"

She nodded, biting her lip. "In June." When he said nothing else, she rushed on. "I wanted to call and tell you the minute I found out. But…" She lifted her shoulders. "You're old-fashioned, Gil. It's one of the things I love about you. You would want this child to have a mother and a father whether you wanted to be with me or not." A moment passed. "I needed to know that you wanted there to be two of us. Before we became three of us."

"Sara, I…" The honk of the ship's horn cut through the air, startling them both. Grissom shook his head. "Should you even be here? Like this?"

She offered him a small smile. "I cleared the trip through my doctor. I wouldn't put our baby in danger."

"Our baby," he repeated, numbly. "We're having a baby."

"We?" she asked, bravely. Hopefully.

Grissom swallowed. "I left the lab, Sara. Turned in my notice, did my two weeks. Catherine is keeping Hank for the time being. I have a moving company who will pack everything I haven't already." He paused. "I've tried my life with you and without you. And I know which one I want." Taking a tentative step towards her, he reached out one hand to touch her stomach. "Just tell me where you want to go…and I'm there."

The ship's horn sounded one last time, their last chance to board. Sara took his hand before he could settle his palm on her belly. "I want to get on that ship." Their fingers entwined. "The rest…we'll figure out together."

They were the last to board and by the time they made it up on the observation deck, the ship was pulling away from the dock. At the railing, surrounded by their fellow passengers, Grissom drew Sara against him for a long, slow kiss.

They stood there, wrapped in each other's arms long after the sun had set, caught between the ocean below and a sea of stars above.

"Darwin arrived at the Galapagos Islands in September of 1835 when he was twenty-six years old." Grissom knelt down on the deck to speak directly to Sara's belly. "You're lucky. You're going to walk in his footsteps before you even can walk."

Looking down at him, Sara ran her fingers through his curls. "Any kid would be lucky to have you for a dad." She turned her gaze up to night sky. "Warrick knew that. You know…he's sort of the reason we're here at all."

"He'd like that," Grissom said with a wistful smile.

"You're really ready for all of this?"

Standing, Grissom guided her chin down to look her in the eyes. "We're in the birthplace of the theory of evolution, Sara." His lips brushed against hers. "I wouldn't have come if I wasn't ready to evolve."

Resting her cheek against his chest, she smiled. "Thank you, Darwin."

Fin