Authors Note: This is my first fanfic :D Any suggestions greatly appriciated. Apologies for the length. Read, review, whatever, just hope you enjoy it :) x

Disclamer: I don't own Castle. I wish I did. If I did I'd bring Series 2 and 3 to the UK faster.

Detective Kate Beckett looked at the mountain of paperwork on her desk and sighed. She had closed the case, a robbery gone wrong, but still had to finish the write up. Ryan and Esposito had already made their excuses and left hours ago, and with the amount of work she still had to do, there was no way she'd get home before 11 tonight. She rubbed her tired eyes, knowing that what she needed was coffee. But just as she was about to go and get some, a steaming mug was placed on the desk in front of her.

"You look tired" He said simply, settling down in the chair next to her desk.

"Thanks Castle" She replied, taking a small sip of the strong coffee, "But you can go home now, it's past 9. You don't officially work here, remember?"

"Yes, I remember." He paused. Watching the way she cradled the coffee mug in her hands. She looked like she hadn't slept properly in weeks. "But just because you do doesn't mean you should be here this late either." He glanced at the work she still had to do, a concerned look on his face, "and by the looks of this you're not planning on leaving anytime soon."

She shrugged, "It's paperwork Castle, it's what we do, you know? After we catch the bad guys" She stopped, seeing the concerned look on her partners face. "Look I'll finish this file and then I'll go. Okay?"

He stood up, putting on his coat. "No, it's not okay. Come on, you're leaving now." He closed the file in front of her. "You can finish tomorrow. And anyway, I'm not leaving here until you do, and you know you'll get no work done if I'm here distracting you."

Beckett knew he was right. Annoying, but right. She needed sleep, and the paperwork could wait until tomorrow. Resignedly she got up from her chair, and grabbed her coat from Castle as they both headed towards the elevator.

"You know you could just let me do my work for once Castle," Beckett objected, as they stepped into the elevator, "I'm fine, I could have finished it."

"Seriously Kate, I know you've not slept in weeks" He paused as the elevator doors closed, a small smile pushing at his lips "and besides, I'm not getting shot just because you can't keep your eyes open in the field"

"Well maybe if you stayed in the car, like I told you to, then you wouldn't end up in the field with a gun pointed at you" She smirked, as the elevator doors opened and they stepped towards the exit.

"Touche Detective, although it might be better if you just got some sleep." They headed into the cool night air, walking towards the taxi that was waiting.

"Tell you what Castle, you take this one, I think I'll walk home. Clear my head y'know?"

Castle shrugged, "In this weather? If you get a cold don't blame me, or infect me. I like my health thank you very much"

She laughed, "Maybe I'll call in sick tomorrow, get away from you distracting me"

"Ahh, but detective, you'd miss me too much" Castle grinned out the window as the cab pulled away from the kerb.

"Don't bet on it" she called over her shoulder as she began to walk away.

She didn't notice the figure that was following her until it was too late.