Disclaimer – still don't own Castle but still wish I did!

Rick's words rolled in her mind over and over – like a tide that simply would not stop. "I have just as much motive to kill him..." She twisted her gold chain with her finger and bit the inside of her bottom lip, a bad habit she couldn't remember when she'd picked up. She was leaned back in her chair, staring across the desk to the empty chair across from her – the one always occupied by Castle. She'd lost count of how many times in the last 48 hours she'd looked up to say something to him, only to find him not there.

She tried to shake the image of his face from her mind – how hurt he'd looked when she ordered him away from the crime scene. She couldn't help but feel like she'd betrayed him, but she had a job to do and he certainly was not aiding her investigation.

Lost in her own thoughts, she unconsciously took a sip of the coffee that had suddenly materialized on her desk before she realized she wasn't alone. "Castle, you can't be here."

Rick sat down on the edge of her desk and looked down at her. "I know, Kate, I'm only going to stay a minute. I just wanted to apologize."

She glanced up at him and swallowed a sob. He truly looked awful. Dark bags circled his eyes and the weight of the last two days sagged his shoulders. "It was...presumptuous...of me to expect my word to be enough for you not to suspect my sister. I'm sorry for that. I'm sorry for my anger. It wasn't really directed at you, it was the situation."

She smiled softly at him. "I appreciate that, Rick."

He shook his head. "I'm not finished. I'm sorry I didn't tell you about Zara. I've racked my brain trying to remember why I never told you I have a sister. I guess...I don't know, I thought you knew, or I assumed you did, or maybe I just expected you to know..."

Ryan interrupted Rick's confession with an apologetic glance at both of them. "GSR test are back." He handed the file to Beckett as Castle shifted his weight uncomfortably.

She opened the file and quickly read the results; then, offered her partner a small smile. "Zara's clothes were clear." Rick's eyes closed involuntarily as relief flooded over him. "Only a trace amount on her hands, most likely from her performing CPR on Chase."

"I told you she didn't kill him," Castle said triumphantly. "What about the security cameras? Did they show the killer?"

Kate laughed gently. "Castle, you know I can't talk about the case with you. You're entirely too close to this one."

Rick nod his head. "I know, I'm sorry."

She offered him a brilliant grin. "You can seriously stop saying you're sorry now."

"I'm sorry," he said quickly.

"Castle!"

He mimed zipping his lips and tossing the key. Kate rolled her eyes. Ryan laughed and shook his head at his colleagues. "I have more," he announced, "if you're cool with Castle hearing it."

Rick look so jubilant at the GSR results, she found herself unable to say no. "Knock yourself out," she answered.

"The security tapes," he began, shooting Castle one of their many hand gestures, which was quickly returned, "didn't show any perps, which is bad news for us. But, it did confirm Zara's timeline exactly, which is good news for..."

"Me," Castle interrupted. Ryan nod in agreement.

"Security feed recorded Zara Chase enter the building's lobby at 10:36 p.m two nights ago. The cameras don't have audio, but it clearly shows her pressing the button for the elevator, reacting to something seconds later, dropping her bags and running out of frame. Stairwell cameras picked her up immediately after. There are cameras in the foyer of the residence part of the building, but not in the living quarters."

"Anyone else seen entering or leaving the building?" Kate asked curiously.

Ryan pulled a photo from the file in his hand. "Cameras picked up this lady leaving at 8:04 p.m." Kate glanced at the photo before handing it to Castle. He shook his head, indicating he'd never met the woman in the photo. "According to Chase Enterprises website, the woman is Natalie Benson, Chase's executive assistant. After Zara, the next people on the feed were our unis responding to the 911 call."

"Natalie have a reason for leaving that late in the day?" Kate asked.

"She said that was actually an early night for her. Working for Conrad Chase was a 24/7/365 job."

"That I can attest to," Rick offered. "The man worked more than anyone I'd ever met and kept his employees on very short leashes, especially his assistants."

"She give you anything else – a list of people Chase had pissed off recently?"

Ryan shook his head. "She said that the last 2 months have been unusually quiet and that Chase had been out of the office more than usual and just generally acting strange."

"Probably the cancer," Rick offered.

Kate's eyes went wide with shock. "You know?"

Castle nodded his head. "Mother told Zara and I later that night. She is very appreciative to you for allowing her to be the one to tell us."

"That's something that probably needed to come from a parent, not some random homicide detective," Kate responded with a shrug.

"You're not a random homicide detective, Kate. Not to me."

She quickly looked away, praying her reaction went unnoticed by Castle. She'd heard his declaration of love for her before she surrendered to the sweet serenity of unconsciousness after she'd been shot. He was by her side almost the entire time she was in the hospital recovering and paid for a private nurse when she'd insisted on going home but refused the offer to stay at his place. For some reason she still couldn't put her finger on, she couldn't force herself to acknowledge Rick's confession, though she desperately wanted to.

"Any other way in or out of the living quarters?" she asked, effectively changing the subject.

Before Ryan could answer, Castle said, "yeah, there's a door that leads to the garage through the butler's pantry, off the kitchen. It's how I would sneak out of the house when I was 14. Conrad only has cameras in the common areas of the house, not the private rooms. When I was a kid, there was only one camera in the garage. If you stayed flat against the wall, you could make it to the door without the camera picking you up...and why are you grinning?" he asked Kate curiously.

She laughed. "Sorry, just the image of you at 14 sneaking out of the house."

"I was not always the bastion of honor, goodness and morality that I am today Mademoiselle," he countered sarcastically.

"And lemme guess, sneaking out might have had something to do with you landing in boarding school?" Kate asked with a grin.

Rick shrugged his shoulders. "I can neither confirm nor deny that accusation, Detective."

Kate laughed again and returned her attention to Ryan. "Any cameras in the garage?"

The younger detective sorted through the file and notes quickly. "Uh, there's nothing in here about a feed from the garage."

"And?" Kate prodded.

"Aanndd...I am going to go back to the guys with the system's server and find out for you..." Ryan answered before quickly retreating down the hall.

The silence left between Kate and Rick at Ryan's disappearance quickly became uncomfortable. Rick spoke first. "I should go...Zara wants to speak to Conrad's doctors about the cancer..."

"Yeah," Kate agreed, righting her chair and pretending to find interest in a report on her desk. She glanced up at him again. "I'm sorry, Rick."

Castle's eyebrows furrowed in confusion. "Why are you sorry?"

Kate shrugged. "I'm just sorry for what you and Martha and Zara are going through."

"Thanks," Rick answered softly. They exchanged smiles and barely whispered goodbyes before Castle turned to head out of the precinct.

"Hey Castle?" Kate asked loudly, just remembering something she needed to ask him. He turned and faced her again. "Yeah?" he answered.

"I noticed a ring on Zara's hand the other night. Is she married?"

Castle shook his head. "No, she said it's an engagement ring. Ivory, from Zimbabwe, where one of the clinics is located."

"You know the guy?"

"No," he answered easily. "Haven't met him yet. Zara said he's coming in to help her with the arrangements and the foundation affairs."

"He's in the clinic with her?" she continued.

"Yeah, she said he's back and forth between the clinics and the states a lot. I think his name is David or maybe Davidson."

Kate's breath caught in her throat and a sick feeling began to develop in the pit of her stomach. "Davidson the first name or last name?" she asked, not really wanting the answer.

"Uh...first...name...I guess." Castle studied his partner's stricken appearance with worried eyes. Why would she have such a reaction to a name, he wondered. "Davidson is the only thing I've ever heard Zara call him."

"Okay, Castle, thanks," Kate said quickly, turning her back to him and rushing back to her desk.

"Kate?" he called after her.

She waved him off dismissively. "Thanks, Castle, I've got work to do."