Author's Note: Just want to quickly thank all of you for reading & reviewing & being so lovely and supportive. You guys are the best!

And thank you again to Andy for the encouragement and brainstorming and ideas, and to Liv Wilder for beta-ing every single chapter and sharing her wealth of information and suggestions with me. I've learned a lot and I really appreciate all of your help!

Chapter 15

"He's not gonna crack," Castle huffed in frustration as the door of the interrogation room snicked shut behind them. "We need solid proof."

"I know," she agreed. "But there were a hundred other people at the bar too, and we haven't found a single person who witnessed Travis dosing Jenna's drink. Or anything out of the ordinary, for that matter. We need more."

"Julian's alibi checks out," Espo relayed, falling into step next to Castle and Kate as they made their way across the bullpen.

Kate detoured to the break room, the guys on her heels. "Figured it would."

"So he must've been telling the truth."

Kate tilted her head, regarding Castle inquisitively. "What are you thinking?"

"Well, Julian obviously didn't know what the aconite was really for. Otherwise, he'd have made sure not to touch it."

"So Travis convinces Julian to give him the vial of aconite," she begins, collecting a clean mug and placing it under the spigot on the espresso machine.

"He wears gloves when he touches it – which, if he was at the restaurant, wouldn't have been hard to come by – but leaves Julian's prints all over it to throw us off."

"But if he was going to so much trouble to frame someone else, would he have thrown the vial away somewhere farther from the restaurant? Somewhere where we'd never find it?"

"Maybe he didn't think he'd get caught," Castle pointed out. "After all, he went to a hell of a lot of trouble to make this look accidental."

"Speaking of which," Espo cut in. "How'd he know to slip peanut oil into Jenna's drink?"

"He must've known her," Ryan hypothesized as he joined the group.

"But there's no indication of that," Kate recollected.

"Right, because only Sara was invited out with these 'friends.'" Castle curled his fingers into air quotes as he spoke. "Not Jenna."

"Maybe he knew through Sara somehow?" Ryan suggested.

Esposito shrugged. "He could've asked at some point, I suppose."

Kate sighed, picking up her now steaming mug of coffee and taking a sip. "Okay, see if you can find anything connecting Jenna to Travis. Unis are searching his apartment as we speak. Castle and I'll go back to the restaurant, see what we can dig up."

"You guys come back to make up more stories 'bout how I killed those girls?"

"They're not made up," Castle asserted firmly.

Travis scoffed. "Really? Cause all that stuff you said before sounded like a bunch of made up crap."

"Was it?" Kate challenged. "We found the vial of poison in the dumpster outside your work. The same poison used to kill Annalise. We know that it was yours."

"We also know that the restaurant uses peanut oil to make their French fries. The same brand of peanut oil was used to kill Jenna. As an employee, you'd have had easy access to it."

"Peanut oil? How am I supposed to kill someone with peanut oil?"

"She was allergic," Castle explained. "All you'd need to do is slip some in her drink."

"I told you, I didn't even know her. How am I supposed to know she's allergic?"

"Oh, and then there's this. Statements from your other friends." Castle pretended to consult the file on the table. As though he didn't already know what was contained there. "Mark and Caroline. You know the ones. We spoke to them again and they said you weren't with them the whole time. No, you disappeared into the crowd for ten or fifteen minutes. Plenty of time to slip peanut oil into Jenna's drink and ditch her purse in a dumpster in the alley around the corner."

He snorted. "Please. That's ridiculous."

"After which you 'ran into' Sara and invited her out with you," Kate continued, ignoring his interjection. "Eliminating every immediate option for helping Jenna."

"There's just one thing we can't figure out," Castle bluffed, leaning forward, blue eyes serious. "Why didn't you kill Sara, too?"

Travis sat back in the chair, folded his arms over his chest and fixed them with a derisive stare. "You guys seem to have it all figured out," he snarked. "Why don't you tell me?"

"Well, Travis made a full confession," Kate announced as she exited interrogation half an hour later. She waited for him to be escorted away by uniforms before continuing. "Turns out he'd been planning this for over a year."

Castle picked up where his wife left off. "It was a tale of revenge. Carly's parents took her death hard, understandably. Her mom moved out of the house and her dad started drinking heavily. Got busted for assault and spent a couple nights in prison."

"So it was revenge on her parents' behalf?" Ryan asked, head cocked to the side in confusion.

"Seems like it, though they had nothing to do with the murders," Kate clarified. "In Travis' mind, all of it was Sara and Ernesto's fault."

"And what better way to make them pay than to take away the people closest to them?" Castle continued. "Just like they did to him."

"He took the job at the sports bar for the sole purpose of getting close to Annalise," Kate explained. "Apparently she and Ernesto frequented the place."

"He was stalking them?" Ryan interjected.

"Seems like it."

"So he waited until she showed up at the restaurant, dosed her beer with the aconite, and no one was any the wiser."

Ryan tilted his head thoughtfully. "What about Jenna?"

"He was in the process of planning this whole thing when she and a coworker happened to show up at the restaurant one day. Told him about her peanut allergy in the course of ordering her meal, and he figured that'd be an even more foolproof way to get away with killing her."

"Both of them," Castle clarified. "Make it look like an accident by slipping poison into their food."

"Or using food as a poison of sorts," Kate added, nodding to Castle.

Esposito jumped in. "Almost worked, too."

"Mmmm," she acknowledged.

"Wait, Sara didn't know Carly was Travis's cousin?" Ryan asked.

"Different last names," Kate pointed out. "Sara had no idea. Guess Travis never mentioned it."

"They knew each other from way back in school but drifted apart for a while," Castle explained.

"Reconnected a couple of years ago, when Sara mysteriously 'ran into' him at a club," Kate added.

"You think that was intentional," Ryan guessed correctly.

"Seems like it."

"And she and Carly were more of the go-out-and-have-a-good-time sort of friends than the talk-about-your-life type," Castle explained.

"And Caroline?" Espo asked.

Kate shook her head. "Didn't know anything about it."

"Small world," Ryan mused.

Kate set the case files on her desk, sank into her chair. "Small world indeed."

"It's just so unfair," Castle lamented as they dismantled the murder board, packed up the files.

"I know, Castle," she agreed.

"They were so young."

"I know," she responded again.

He shook his head, Jenna's picture clutched in his hand. "All because of an accident."

"We got him," Kate reminded him. "We found justice for their families and for Sara and Ernesto."

"That doesn't bring them back."

"No, it doesn't," she murmured sadly, eyes dropping to the photograph of Jenna. Two young, smart, beautiful women taken from this world far too soon, and all because of some misplaced anger.

"But hey," she began hesitantly, slipping the picture from his grasp and placing it in the box with the rest of the materials from the two murder boards. "We solved the case. We proved that we can do this."

"We did," he agreed proudly. It wouldn't be easy, and he knew they'd both likely find themselves fighting to hold back. But they'd proven today that they could do this. They could be married and still be professional, still solve crimes.

"We're gonna make this work," she assured him. "I promise."

"Yeah?"

Kate secured the lid on the box, smiled gently. "Yeah."

"How's Alexis doing?" Kate murmured as Castle slipped into bed behind her, setting aside his phone before extending his legs under the covers and molding his body to hers from behind.

"She's fine. Still thinks I'm overreacting, but she promised to be careful and that she'd always call if something seemed suspicious."

Kate nodded into the pillow. "Good."

"You think I'm overreacting too," he profiled.

She rolled onto her back, turned her head to face him. "I think that you can be over protective," she admitted. His face fell but she stopped him with her next words. "But it makes me feel safe. And loved."

"You are."

"I know, Castle." She smiled, a dazzling, beautiful thing, couldn't reign in her emotions. The things he did to her, even after all this time. "I'm pretty damn lucky."

He dipped his chin to capture her lips in a deep kiss, melding everything he couldn't find the words for into the tender, loving gesture. Six years and he still found himself at a loss of words. "No, Kate. I'm the lucky one."

END