Here's another actiony crime fic- because that's the way i roll ;) I started writing this before Pandora and while i suppose it could still fit anywhere in season 4 i'm thinking prior to that mindbogglingly amazing two-parter would be a safer place to put this.

Huge thanks to Trish for reading through the first bunch of chapters and helping me to get it somewhat more organised! Ta, ta, ta, ta!

I'm a fair way in front of what's posted (just making sure i keep things straight before uploading) but it is still unfinished. They turned into mushy fluff-balls and I kept writing so I'm not sure where i'm going with it! LOL! But i'm amusing myself and keeping out of trouble so it's all good. And I intend to write often and update frequently so it's not going to be a long drawn-out epic.

I'm always up for comments and feedback (whatever your opinion), and also happy to chat cos now i'm on twitter mojordreaming. And as wonderful as updates and favourites are, i gotta admit reviews are TOTALLY so much fun, and knowing someone is enjoying reading really adds motivation when i'm sitting in front of the laptop thinking 'what the hell am I doing?'.

Erosion
Prologue

With their plates long empty and the comfortable silence stretching between them Castle recognised the shift of her body and knew she was gathering herself to make a move and head home.

The warmth of the apartment and her full belly made it almost impossible to shift herself off the couch, but with a resigned sigh Beckett stood up. With a similar lack of enthusiasm Castle followed her.

Her gait was without her usual vigour as she headed to the door and reached for her boots. Castle watched as she leaned against the wall and pulled them on. Dressed in his too-large sweatpants and one of Alexis' hoodies, and her hair pulled back in a loose ponytail, she looked far more vulnerable than he was accustomed to seeing her. He waited while she gathered up the folded pile of her clothes, fresh from the dryer, and then held out her coat. She slipped one arm in and turned a slow circle as he wrapped it around her. He fought the urge to bring her in against him for a hug.

Instead he pulled the sides of her coat across her stomach and reached for the belt. She fought off a yawn, and Castle rested his hand at her waist when she wobbled on her feet.

"Are you sure you're okay to drive?" he asked quietly.

"Mmmm, I'm fine, Castle," she let out a tired sigh, "I just want to get home and sleep until I absolutely have to get up."

"Text me when you get home so I know you're safe. Please?" He'd already made the offer of his guest bed, but he was tempted to make it again.

Her hand lay briefly on his chest and the lack of strength in her did little to reassure him despite the brave smile she offered. The smile turned into another yawn. When Castle followed automatically with a yawn of his own they both chuckled quietly.

"Sleep well, Castle. I'll see you tomorrow." His solid warmth called to her, and she was past thinking as her hand drifted up over the curve of his shoulder towards his neck.

She was moving up towards him, her eyes closed, before he had a chance to realise her intention. Her mouth settled over his – the gentle press of lips – her mouth closing around his top lip with a slight increase of pressure before pulling away.

Castle felt the world shift under his feet and, as she stepped back, his body sought to follow her; he wanted nothing more than to hold her against him and kiss her again. The catch of her breath reminded him to breathe.

She groaned, annoyed at herself, "I'm sorry, Castle, I must be more tired than I thought." She dropped her head and started to step away. With her heart skipping in her chest she felt light and euphoric; another surge of adrenaline through her already exhausted and sleep-deprived body.

"Kate?" One hand moved to wrap lightly around her back, not restraining her but urging her to stay close. "It's okay." He tried to reassure her.

"I wasn't thinking." The goodnight kiss had felt all too natural. Even now she wanted nothing more than to collapse against him.

Castle slid one hand against her cheek and lifted her face. He was amazed that she allowed the intimate touch. "You're exhausted. Just stay here."

The low timbre of his voice threatened to draw her in. "I can't," she resisted, but even to herself her voice sounded uncertain. The gentle caress of his thumb across cheekbone had her fighting to keep her eyes open, and she pushed away to untangle herself from his touch. "I'll see you later?"

Castle battled with himself. They'd both been on edge for a solid twenty-four hours; running on nothing but adrenaline and coffee. He was fighting to stay on his feet and she looked ready to collapse. He wished he could give in to his own desire to just wrap her in his arms and reassure himself that they were both okay. But he knew too well how quickly she would withdraw if she felt her balance threatened.

Her kiss, so impulsive and unexpected, revealed more than anything else that the barrier she worked so hard at maintaining between them was wavering , at least for tonight, and that her body sought comfort in his presence just as he did in hers.

He hesitated for an instant, afraid of forcing her to retreat further, but the grey shadows under her eyes made up his mind.

"No," his voice was gentle but he wasn't negotiating any longer, "We've had a hell of a night, Beckett." His hands were already untying her coat.

"Castle, don't." Despite her protest there was no strength in her voice.

His hands stilled, but he didn't let go of her belt. "I'm not going to have us survive an armed ambush, being abducted, an exploding boat, and the freezing waters of the Atlantic only to have you wrapped around a streetlight because you fell asleep on the way home. Sometimes it's okay to admit that you're not invincible; that you need something."

"I'm feeling anything but invincible at the moment. Tonight was one close call too many, Castle."

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