Chapter 6

Much to Castle's dismay, Kate spent the rest of the afternoon filling out paperwork and preparing to dismiss the case. Jenna's death had officially been ruled as natural causes - tragic, no doubt, but displaying numerous signs consistent with those of congestive heart failure. Though it was incredibly rare in someone of Jenna's age, it wasn't unheard of. And with nothing from the tox screen or final autopsy report, they didn't have the grounds to declare it a homicide.

Despite his efforts, even Castle had to admit that there wasn't much to suggest foul play. Unless CSU found something on the purse, they had almost nothing. Maybe it really was just a coincidence.

Statistically unlikely. Very much so. But he was reluctantly willing to concede that it was in fact possible.

Still, he couldn't shake the feeling that there was something they were missing. Maybe something that wasn't picked up by the tox report, he silently wondered. There were poisons designed to cheat the system, right? Castle dug his phone out of his pocket and opened the browser app to do a bit of research, completely losing track of time as he found himself enmeshed in the world of lethal poisons and various substances chemically engineered to evade detection.

None of them particularly appeared to line up with Jenna's post-mortem conditions. However, he soon found himself laden with all sorts of ideas for the next Nikki Heat novel. An undetectable poison administered by an enigmatic assassin, leaving Nikki and Rook to track down the killer. He'd call it Venomous Heat. And he'd give Lauren Parry a chance to shine, have her be the one to uncover the mystery. There'd be something in the tox screen to indicate an accidental death. Maybe an overdose, maybe an unfortunate combination of medications. Maybe a poison of some sort. Something someone snuck into her food.

Wait. Sara had said that Jenna worked in a medical research lab. Her parents had said something about her studying the immune system. He couldn't recall all the medical terminology but regardless, a lab like that had to be full of potential powerful toxins.

He needed to examine the autopsy report again.

Kate nearly fell out of her chair in surprise when Castle suddenly jumped to his feet, phone in hand as he hurried across the bullpen, a pleased smile on his face. Whatever he'd been doing on his phone for the last two hours, he'd been unusually silent and secretive about it, and she couldn't help but feel suspicious.

He was obviously up to something.

"Hey."

Castle startled, whirled around, hot coffee sloshing over the edge of the mug and onto his thumb.

"Ow, ow, hot," he gasped, sucking the finger into his mouth in an attempt to soothe the burn.

"Sorry," she murmured, stepping up next to him and taking over the coffee duties while Castle rushed to turn on the tap and run a stream of cool water over his finger. Kate poured coffee into the other empty mug he'd set out, stirred a bit of creamer into each and added a small spoonful of sugar to Castle's mug as well. She tossed the stirrer into the garbage, lifted her mug to take a drink.

"Finished the paperwork?" he asked pointlessly as she set mug back onto the countertop.

"Mostly," she answered with a half-shrug. "Finished whatever you were working on?"

"What d'you mean?"

"You were practically glued to your phone for two hours."

"Oh, that," he answered easily. "Just doing some research."

Mmmm. Right. Of course he was.

Kate raised an eyebrow disbelievingly. "Nikki Heat?"

He shrugged, turned off the tap and held his thumb up for examination. "Possibly." He bent the digit, winced as the reddened skin stretched over his knuckle.

"Let me see," she murmured, gently grasped his wrist, holding his hand in place as she stepped into his personal space. She could see where the liquid had spilled, and the area was a bit inflamed, but nothing he wouldn't bounce back from fairly quickly.

"Kiss it better?" he asked with a mock pout, fixing her with his most convincing puppy-dog eyes and batting his eyelashes. Completely adorable. And completely inappropriate for the workplace.

"We're at work."

"But it hurts."

She dropped his hand, rolled her eyes in an attempt to repress her body's reaction to him. "It's just your thumb. You'll survive."

"But it's my right thumb," he pointed out, as though this made some sort of difference.

"So?"

"So I'm right handed."

"Again, so?"

Castle reached out, settled his left hand on her hip, fingers splayed wide, thumb tracing the ridge of her hipbone. "So I seem to recall you being rather fond of my fingers," he articulated in a low voice, left thumb sliding lower, dipping beneath the fabric of her pants. "Particularly my thumbs."

Her hips instinctively twitched into his touch as his nail scraped along the edge of her underwear before withdrawing. A pleased smile split his face as she leaned into him, chasing his fingers even as he dropped his hand, shoved it firmly into his pocket. He stepped back, picked up the mug of coffee, and headed for the door, leaving Kate frozen in place, every fiber of her being strumming with unquenched arousal.

Damn him and his sinfully talented fingers.

She couldn't stop staring at his hands. The movement of his thumbs over the touch-screen keypad on his phone. The dexterity as he twirled the white board marker between his fingers, absently spinning the writing implement around and around. The tapping of his thumb against his pant leg as he studied the murder board that she hadn't yet taken down, unwilling to relent in his determination to find Jenna's killer.

And she should've been helping him. She should've been rechecking financial records and digging up any background on Jenna, because Castle was right. Something didn't add up.

But all she could think about was the soft touch of his hands on her skin, the thickness of his fingers, the way he could so easily reduce her to a quivering, helpless mess with just the work of his hands.

Just the thought of it made her tightly cross her legs, a not-so-discreet attempt to disguise the intensity of her body's reaction to him.

Five o'clock could not come soon enough.

By the time they arrived at the loft, Kate was so riled up that she pressed him back against the door, slamming it shut with his back as she practically climbed his body.

"A little eager, are we," he teased with a saucy smirk, hands spanning her ass as she hoisted her legs up and locked them around his waist.

"Shut up."

Her fingers found the buttons on his shirt, deftly slipping each tiny disk through its hole until her hands could slip beneath the fabric, spanning warm and wide over his chest. He turned them around, pressing her back against the door as she pushed the shirt over his shoulders, tugging the sleeves down his arms, and he released his grip on her one hand at a time to allow the garment to fall to the floor.

Kate was just loosening his belt when her phone vibrated in her back pocket. Her hips instinctively bucked into Castle's and he groaned, dropped his head to her shoulder.

"Ignore it," he demanded, voice rough with arousal.

She sighed, dropped her head back against the door as she unwound her legs from their iron grip on his waist. "I can't."

She extracted the phone, a frustrated sigh escaping at the 12th Precinct flashing up at her. Kate cleared her throat, answered the call.

One look at her face said all he needed to know.

The case on Jenna being all but closed meant that they were once again available and on call for the next unlucky victim.

And it looked as though he or she had just been found.

Thoughts?