A/N: Prompt at the bottom of the shot in order not to leave any spoilers. It was sent to me through tumblr, so thank you! And hope you all enjoy it!

Castle sits at his desk when he hears the shower turn on in the guest bathroom and has to fight the urge of imagining the detective getting undressed under the same roof as him. As he tries his best to continue writing the scene he has in front of him, and not turning it into a sex scene in the shower, he hears the shower turn off again. Furrowing his eyebrows he can't help but look up at the roof, she can't have showered that fast. After a few seconds he shakes his head and goes back to the writing.

"None of your business," he sing-songs to himself.

Then he hears it again, the shower turning on. He stops tapping on the keys for a second, just listens, and after another few minutes the sound of the shower stops again. Something's not right. Castle stands and starts to walk to exit his office when he stops to think. Is this really any of his business? Then he hears the shower turn on and off once more and it decides it for him. Yes, it's his business. If nothing else he could blame his curiosity on the water bill. As he walks up the stairs and comes face to face with the door for the guest room he hears the sound twice again.

"Beckett?" he calls as he knocks on the door. "You okay?" He waits a few seconds before he knocks again. "Beckett?" No answer. "Kate?"

The door suddenly opens with just a crack being in view to him, his partner looking at him with annoyance and… something else, in her eyes.

"What?" she asks irritatedly.

He swallows. Hard. "Is the water not working like it should? Should I call someone to fix something?" he asks and he can see a small blush of embarrassment on her cheeks.

"No," she says.

"Then why… why do you keep turning on and off the shower?" he decides to be honest.

Her blush deepens and she looks down. When she still hasn't said a word for another minute he opens his mouth again.

"Kate, what's wrong?"

Castle falls quiet then, feeling that it's up to her now if she wants to tell him or not. And if she decides not to then it's not up to him anymore. He has to respect her wishes.

"I can't… shower," she whispers under her breath and he looks at her, still looking down.

"You can't… shower? Wh-is the water too cold? Too hot?" he starts asking but stops the questions when he sees her shaking her head. "Then what?"

She opens her mouth but when he expects her to say something he sees her closing her mouth again before leaning her head back while groaning and he observes her eyes are watering as well.

"I can only think of him, how close it got," she whispers. "I can't stop hearing the message play every time I turn on the shower."

At first he's not following her. But then he understands it all, the message she's talking about. Goodbye Nikki. Goodbye Nikki.

"Can I help?" he asks and she looks up at him with narrowed eyes. The sadness and torment still evident in her beautiful hazel eyes. "Not like that. Honestly. Anything. Bring you something that could help."

He observes as she thinks for a few minutes. A ray of emotions struggling across her eyes before she silently steps back and opens the door slightly in order to let him inside.

"Keep me company? No peeking just… please?"

He smiles carefully. "Of course."

When he comes inside the room he sees she's only dressed with a towel wrapped around her, reminding him of how she must've been when he called her to warn about the murderer still being alive and after her. He gulps as he remembers the fear he'd felt when that bomb went off and he saw her apartment explode with flames.

"Where do you want me?" he asks as they enter the bathroom and he observes her facial expressions as she thinks.

"I…'m not sure," she tells him and when she looks towards the shower he sees her wince before she's biting her lip.

"How about I sit here, on the floor, facing that way?" he suggests and points on the mat on the floor while facing away from the shower, giving her enough space to drop the towel as well without him seeing anything.

She nods, hesitantly. "Y-yeah, that sounds good."

It's so weird, seeing his partner being this insecure, this… agitated. And so he sits down without another word and faces the way he promised and listens as she turns on the shower once again. She takes deep breaths and he can still hear the hesitation in her inhales and exhales.

"Breathe, Kate. He's gone, he can't hurt you anymore," Castle tries to say in a low but considerate tone.

"I know that," she bites through her teeth and Castle just ignores it.

"I'm right here, you're not alone. No bomb is going to go off because there is no bomb anymore, Kate. It's safe," he continues to say in the same soothing voice and he hears her take another breath before he hears a step being taken into the shower stall.

He stays quiet for a while as he hears her shower. He's constantly fighting the urge to turn around but does that pretty well since he's trying to think about why he's sitting there in the first place.

"This feels ridiculous," he hears her mumble and he takes a quick breath before he asks.

"Why?"

She sighs and he has to focus his eyes on the trashcan to be sure he won't accidentally look at her.

"Because I should be able to take a shower by myself, I'm not a kid anymore," she says with an irritation obvious in her voice. "If someone finds out… I'll be the laughing stock of the precinct."

"Don't worry, my lips are sealed," he promises. "And it's not abnormal, Kate. You almost… died in that only thing chasing my nightmares away is the fact that you're under the same roof as me," he confesses and bites the insides of his cheeks. He hadn't really meant for his confession to slip out.

It's quiet for a couple of seconds before he hears her rinse her hair, at least that's what he assumes she was doing. "You have nightmares?" she asks then, her voice careful.

He nods, even though he doesn't know if she's looking at him or not. "Yeah, in the nightmares you don…" He takes another deep breath. "Let's just say that waking up and remembering you're just a few steps away makes it a bit easier to fall back to sleep."

She hums and he waits for an answer, if there will be an answer. He hears the water stop running and yet again has to fight the natural urge to turn towards the sound. He closes his eyes and rolls his thumbs, just being there, that's the only thing she asked for, him being there.

"Thank you," she whispers and he automatically looks up to her, her voice being so close.

"Always," he says and she smiles at him.

He stands up and walks out with her right behind him. Before he reaches the door she says his name, his first name, and he stops to turn to her. He's frozen in place when she comes closer and just stops right in front of him, standing on top of her toes, and pecks his cheek.

"I mean it, thank you," she says again.

He smiles and nods, tries to burn the scene into his memory. She looks so beautiful and he can't wait to see what this new side of the badass detective means. But right now it's time for him to leave so she can get dressed on her own.

"I'll start the dinner, it'll be done in thirty minutes," he informs her and she nods.

"I'll be there," she promises with a beautiful and shy smile.

"Good," he says and takes one last glance at her before he walks out.

THE END

Prompt: "Hey you, I recently red in Twitter about Beckett being scared of showering, because of what happen with the "goodbye nikki"-thing, and I thought maybe, of course only if you have time, you might want to write a little fanfics about it😊. But if not, I'm totally okay with that either. Have a great day!"

Thank you so much!