A/N: Set several weeks after Killer App.

Walking into The Lightman Group, Cal's ear perked at the sound of giggling.

Giggling? Yes, definitely giggling…from Gillian's office?, he wondered to himself.

Intrigued, Cal headed in the direction of the seemingly out of place laughter. Approaching her office, he saw Gillian typing something on her computer with a completely delighted smile on her face.

"What's so amusin'?" he asked as he sat across from her.

"Hmm?" she asked as she looked up at him, trying to stifle a smile. "Oh, it's nothing."

Cal narrowed his eyes. "Nothin' doesn't make you smile like that," he said as he pointed at her. "Out with it."

"It's personal, Cal," was her only response.

He took a moment to consider respecting her need for privacy, and then he quickly jumped from his chair and rushed around her desk in time to see an instant message box being closed on her screen.

Spinning in her chair to face him, Gillian crossed her arms over her chest and simply looked up at him.

"Really, Cal? Personal means it's meant only for me," she replied, only half surprised at his actions.

Another message popped up on her screen.

Mark: See you at 6. Can't wait to see you.

"Mark, huh?" Cal asked, his blood turning to ice. He could feel his heart rate increasing, both anger and fear rushing through his veins. After Claire, he found himself needing to be around Gillian more than usual, or maybe it was a want. Either way, he found it increasingly difficult to maintain his distance from her, to keep his hands to himself. He'd been keeping his distance because he thought she was still grieving. He'd made himself available to her, like he always was; but he went out of his way to make sure she was alright, to give her an extra hug, to be less of a bastard than usual. And now it seemed he'd waited too long. She'd found someone else. He swallowed at the thought of having lost her to another man.

Turning around in her chair, Gillian looked at her screen and sighed. So much for keeping this personal. "Yes, Mark."

Cal raised his eyebrows in silent thought and left her office without another word, leaving Gillian looking after him and wondering about his sudden, silent exit. Several people attempted to talk to him on the way to his office. He couldn't tell you who though, he was too focused on getting to his office without punching something or verbally accosting someone. He tried to hold it in, for her, because she deserved that much after what she'd been through.

Images of a blood-covered Gillian entered his mind. The blood of someone she had cared about soaking her clothes and turning the flesh of her hands deep red. He swallowed at the memory of her sitting in the police station, bravely telling the story of what had happened, refusing to cry as lone tears streaked her face.

He pulled his hands across his face, no longer wanting to think of her in that moment, so broken and vulnerable. He moved to his couch and sank deeply into it, hoping it would swallow him whole.

Truth be told, he was having trouble distinguishing exactly what he was feeling. Anger at himself for waiting too long? Sadness that she still couldn't see he cared for her? Remorse for having any negative reaction to her trying to find happiness? Regret at all the lost time? The only thing he did know was that whatever he was feeling was paralyzing. Normally he'd run off somewhere and drink himself silly so he could forget. This time, however, he could hardly move.

Somewhere beyond the walls of his office, he heard it again. Giggling. Bloody fuckin' gigglin'.

Then, a new emotion shot through every raw nerve ending in his body: pure jealousy.

He wanted to be the one to elicit that giggle from her and cause a euphoric smile to grace her lips. He wanted to be the one to make her happy. He wanted to be the one to take her to dinner, be the one she got dressed up for, be the one she went home to at night.

Self-pity wasn't going to accomplish anything, though. So he pushed himself up from the couch and headed toward the giggling once again. It was coming from the kitchen, and as he approached, he noticed it was headed toward him. As he opened the door to walk in, Gillian was headed out, looking at her iPhone with a sweet smile on her face. Glancing up, she saw Cal holding the door open and her smile slightly faded. Swallowing, Cal held the door open with one hand and indicated with the other for her to walk out.

Feeling a little surprised, Gillian gave him a small smile before looking down at her phone once again. She said a quick but grateful, "Thank you," as she walked past.

Cal half rolled his eyes and allowed the door to close without entering. He did a 180 to see her walking down the hall back toward her office. Having no reason to follow her there, he simply returned to his office, more jealous than before.

A second later and just missing each other, Gillian stopped in her tracks and turned back to look at Cal. She saw him walking toward his office with his head hung low as he squeezed the back of his neck with a hand, the other balled up in a fist. She pushed away an uncomfortable feeling from within as she felt a wave of uneasiness rise in her chest.

Dropping her hand with her phone to her side, she looked around to find herself alone in the hallway. Biting the inside of her cheek, she headed back to her office while trying to figure out the odd interaction she'd just had with Cal.

###############

Later that afternoon and after several failed attempts at finding a reason to enter Gillian's office, Cal opted for coffee. He went down the street to the coffeehouse on the corner and ordered her favorite – tall, nonfat, caramel macchiato.

As he approached her office, he was pleased to see no coffee cups on her desk and Gillian looking as though she could use a pick-me-up.

"Caramel macchiato?" he asked, standing in the doorway.

Gillian looked up with a wide smile and said, "Yes, please!"

Cal walked in, handed her the cup and said, "Here you are."

"Coffee from the kitchen would have been good enough, but thank you." She leaned back in her chair, wondering what made him go out of his way to get her favorite drink when he usually opted for tea in the afternoon. Taking a sip of her beverage, and closing her eyes at the warmth as she wrapped her fingers around the cup, she asked, "Did you decide you wanted coffee this afternoon?"

Shrugging his shoulders, he replied, "You haven't gone out for coffee in a while. Figured you might want your favorite."

She smiled sweetly at him, loving that he knew these little details about her. She licked her lips and said, "Well thank you. That was very thoughtful."

Nodding at her, he got up from the chair and headed for the door.

"Oh, Cal!" she called after him.

"Yeah, love?" he asked expectantly.

"Here's that file you wanted," she said as she held out the folder to him.

"Thanks," he said, taking the folder from her as disappointment spread from his chest. He heaved a sigh once he was in the hallway, and wondered what else he could pull out of his bag of subtle tricks.

Watching him leave, Gillian bit her lip at his tone of voice and looked sadly at her coffee. She ran a hand through her hair and turned back to her computer, hoping she could find something to distract her through the end of the day.

###############

At 5 o'clock, Cal found himself in the lab with Gillian, Eli, and Ria. He had yet to find another reason to wander into Gillian's office, so he was happy when a late case came in. It seemed pretty open and shut, but it gave him a reason to be in the same room with her, at least long enough to tell Eli and Ria to do their jobs because this case seemed as simple as tying your shoes, unless you were three, which Eli sometimes acted like.

While the other two went over video footage, Cal walked over to where Gillian was standing.

"What'er you wearin' tonight?" he asked casually.

Gillian shot him an annoyed look and shook her head.

"Hmm, can't say I know that outfit," he quipped.

She chuckled and pursed her lips in an effort to hide a smile.

Looking at her sideways, Cal smiled. Refocusing his eyes on the screen where the video was playing, he said, "You should wear that blue dress you wore to work a couple a weeks ago, if he hasn't seen you in it."

Gillian furrowed her brow and turned her head to look at him, question written all over her face.

Momentarily looking at her from the corner of his eye before looking forward again, he said, "The one with the criss-cross thing. Brings out your eyes."

She straightened her posture as surprise registered on her features.

"Not to mention the way it compliments your body. Pretty hard to miss if you've got a pulse." He finally looked in her shocked eyes and added, "Just a suggestion." He walked across the room, leaving Gillian standing alone, wondering what to make of what he'd just said.

My eyes, and my body? Her heart skipped thinking about him noticing her like that. Yes, he often times looked her up and down, but this seemed different. He remembered a specific dress of hers that she'd worn two weeks ago!

Curious, she walked over to him and quietly asked in his ear, "What shoes should I wear?"

###############

Ria looked over at her bosses from her spot in front of the screen and pulled her lips into small 'o' shape as she watched Gillian step incredibly close to Cal and whisper something in his ear. She kicked Eli under the desk, earning a yelp and a, "Hey!" from him. She quickly shushed him and pointed toward their bosses.

Eli turned around just enough to see Gillian stepping away from Cal with a question resonating in her eyes. Eli narrowed his eyes and looked back at Ria. She shrugged at him, and they both turned back to see a self-satisfied smile spread across Cal's face before he stepped back from Gillian. His eyes dropped, seemingly, to the floor. The two protégés again looked at one another and watched an exchange they couldn't hear.

###############

At Gillian's question, Cal stepped back from her and examined the shoes she was wearing. "You have a pair like this that are black, yeah? A little bit taller with a strap around the back?"

Gillian's eyes went wide. "Yes, I do."

"Wear those. Killer on your calves," he said as he stepped into her once again, hunger rising in his eyes. As soon as he did, he noticed they were being watched.

"You crack this case yet?" he asked, still standing very near the shocked Gillian.

"The guy's a liar," Ria said with a knowing smile. "He's been embezzling from his company for years."

"Right you are, Torres!" he said. Turning his head back to Gillian he quietly added, "I suppose you've got a date to get ready for."

Gillian parted her lips as if to say something, but Cal quickly walked away before she had the opportunity.

"What was that about?" Ria asked.

Staring after Cal, Gillian truthfully said, "I have no idea."

Ria looked at Eli with a "yeah right" look and shook her head.

"What was that about?" Eli asked Ria after Gillian left the room.

"Seriously?" Ria asked back.

"Typical 'Lightman wants Foster but won't admit it' stuff?" he queried.

"And 'Foster wants Lightman but she's too blind to see he wants her' stuff," Ria said, organizing a couple files and heading for the door.

"Ah," Eli said, turning off the lights in the room as they walked out. "All in a day's work."

More to follow in a few days!