between the shadow and the soul

I do not love you as if you were salt-rose, or topaz,
or the arrow of carnations the fire shoots off.
I love you as certain dark things are to be loved,
in secret, between the shadow and the soul.
- XVII (I Do Not Love You), Pablo Neruda

They cuff him, and he looks to Kate for reassurance, for something, for anything.

He finds Detective Beckett looking back.

Castle won't look up at her.

Not that she blames him exactly. He hasn't even spared a glance at her since the interrogation and the accusations and the comments. Kate supposes that if their positions were reversed, she wouldn't even be able to stand being in the same room as him, let alone look at him. But the situation is not reversed, and she wishes he would just explain everything to her. Of course she never wanted to arrest him. Even with the mix of his and the victims' past, she would never do this as some sort of petty personal vendetta. She's arrested him before; those times were different, they were different, but this is the only time she's ever really believed him to be guilty.

She wished she didn't.

"Castle."

Kate leans against the wall opposite lock-up, feeling her Beckett persona slip away from her as it always did whenever she was alone with him. It hurts, to slip from composed Detective to weary girlfriend, but it's a natural process for her now. She doesn't have to work so hard to be the person she's always wanted to be. In times like this, she supposes it's something, at least.

"Please look at me."

But he won't look up at her, simply chuckles darkly under his breath and stares at his clasped hands. Kate feels a flare of anger in the pit of her heart. She's not the one who's in the wrong here. He's the one who can't provide an alibi for the murder. He's the one who can't explain how his prints got into the victim's apartment. He's the one who refuses to explain the jewellery. She had just been doing her job.

"Look at me, Castle. Now."

The words hang heavy in the air for a moment and she shivers, suddenly grateful that no-one else is around, and that he won't look up at her. That way he won't see the grip her fingers have curled around her forearms, the trembling of her fingers…

That's when Castle finally speaks.

"Is that an order, Beckett?"

The words stab into her heart, oozes pain everywhere and she flinches involuntarily.

"Don't be childish. I'm here to talk to you, Castle."

That's when Castle finally looks up.

Some part of her wishes that he hadn't, wishes instantly that she could reverse the movement of his head, the way he's looking at her. There's too much pain and heartache and accusation in his eyes that she put there. She looks away.

"No, you're here to get a confessions out of me."

She doesn't rise to the bait, instead swallows back the bitter tears that threaten her pride and pushes off the wall, stepping towards lock-up.

"No I'm not, Castle. But I would like you to explain a few things to me."

Castle barks a laugh, and his eyes meet hers again. It's too much.

"Yeah, of course you do. What, so you can run off to Ryan and Esposito and charge me for murder?"

Castle stands of his own accord, and she notices his body is trembling from head to toe, as if someone has set all of his nerve endings on fire.

"No." She assures him patiently. "Just for my own peace of mind."

Castle studies her for a moment more, before sighing, stuffs his hands that have formed fists into his pockets. Kate assumes it means that she can go ahead and ask questions, so she does.

"Why were your prints at her apartment?"

Castle's head jerks back towards her, eyes wide and wild and a fire flaring in his eyes. "You said that these questions were for you. Not the investigation."

But they are for her. She couldn't care less about the investigation right now, she needs to know why his prints were there, why he was at the apartment of the victim. Her own mind can only conjure one reason as to why he was there, but she can't handle that thought, so she continually pushes it to the back of her mind, ignoring it.

"Why were you buying her jewellery?"

Castle shakes his head, makes a sound in the back of his throat that almost sounds like a whine. "I can't believe this. Leave me alone, Beckett."

Kate simply steps forward again, feels the anger trembling through her bones. "No, Castle. You answer my questions. Stop running away and hiding the truth. You punished me for lying."

He flinches at that, and Kate wishes that she could take the hurtful words back, the fire in her voice.

Castle doesn't answer.

"Were you sleeping with her?"

The question bubbles from her before she can stop it, loud and accusing. She was supposed to have asked that in the interrogation. But she just couldn't. Not with Ryan and Esposito behind the glass and an answer that had the potential to break her heart.

There's a stretch of angry silence, and Castle turns his back on her when he speaks. "You think I was cheating on you?"

Kate swallows thickly, pushing away from the wall to step closer. "I don't know what to think anymore, Castle."

"You think that lowly of me that you could…" Castle trails off, still turned away from her. "That you could think of me as a murderer and a cheater?"

The way he says it, with a bitter taste in his mouth and a bite to his voice, makes it sound terrible. But inside her head it makes so much sense. It makes the books and the obsession with murder and getting inside a criminals mind make sense. It makes the blondes and that reporter and his failed marriages make sense. Kate would give anything to stop thinking this way, to stop the images in her mind, but he won't give her anything to work with. How can he expect so much from her when he's not willing to give her anything in return?

"I don't think lowly of you, Castle. I-"

She wants to say I love you. But she hasn't said it yet and saying it now sounds wrong, like a manipulative way of saying the words. So she keeps quiet, waiting patiently for him.

Castle turns to her then, shaking his head with his jaw clenched. "Get out, Kate. Get out."

"No, Castle, please just explain to me because none of this makes any sense." Kate pleads, stepping forwards and resting her forehead against the bars, feeling the cool metal dig into her skin, a welcome reassurance. "Please."

Castle steps towards her on the other side of the bars, raising one hand to lie on the bars, palm facing forwards. Her own hand rises of its own accord, placing it over his on her side of the bars. It makes the tears sting her eyes even more, and she bites down on her lip and screws her eyes shut tight in an effort to keep herself under control. She can't believe that this is happening. Why on Earth is this happening?

"I've no doubt about your skills as a Detective, Kate. But you need to forget that this is about me, or you, or these stupid, stupid ideas you've got in your head right now."

Kate's eyes open again and she stares at him with a blurry vision, forcing her lungs to keep taking deep breaths. "They're perfectly logical ideas, Castle. If it was me who had no alibi and me who'd been buying presents for the victim and me whose fingerprints were at the apartment, wouldn't you want to… To know?"

Anger flashes across Castle's face briefly, but he fights it down and remains composed, giving away his anger only with the slightest twitch of his fingers.

"Why the hell would I cheat on you, Kate? I've been in love with you for years, and now that we're together, you think that I'd just throw that away? If you think that, then you really don't know me at all."

Castle retracts his hand from the bar then, and walks back to sit down on the bench in lock-up. He sighs deeply and clasps his hands again.

"Go, Kate."

Those three words still choke in her throat, and she still can't figure out what is going on, or why Castle won't answer her questions.

But she turns and walks away, each step making her less Heartbroken-Kate and more like Detective Beckett.

She hides away when they release him.

Alexis and Martha come to collect him, and she sends Ryan and Esposito to deal with it all, hidden away in a cubicle in the bathrooms, trying to compose herself. But her heart is heavy in her chest and the tears streaming down her face are hot and won't stop. It shouldn't hurt this much. It didn't hurt this much before. But she hasn't given herself a chance to be hurt, has focused on proving it wasn't him and now that she has proven it wasn't… Well, it's all hit her now.

She had been so close to losing him.

How stupid could she have been? Of course, the evidence had pointed at him, but the evidence didn't always speak the truth. It had been her own stupid, jealous mind that had taken over during the investigation.

How will he forgive her? If it were the other way around, she wouldn't him.

So she hides and waits for some sign of forgiveness from him.

Around midnight, as she lies wide awake and lonely in bed, there's a knock on her door.

She scrambles out of her bed immediately; dressed in only his shirt with her hair scraped back in a ponytail, face a mess of blotchy cheeks and red-rimmed eyes. But she doesn't care. She doesn't care, because it must be him, it needs to be him.

Her heart hammers in her chest as she opens the door to find him on the other side.

"Castle."

He doesn't wait for her to step back to let him in, instead brushes past her and heads for her front room. She closes the door with trembling hands, turning to follow him to where he's stopped in the middle of the room.

"Kate… I'm not going to pretend like your actions didn't hurt me."

"Castle, I-" She starts, but he waves a hand, and talks over her.

"I understand. I understand why you had to do your job. But, Kate…" Castle steps towards her, takes her hand. "I will never cheat on you. You need to know that. How could you not know that?"

Kate stares down at their clasped hands, grips onto his tightly. "I…" She wants to explain it, she does, but she doesn't know how to go about that without hurting his feelings, without dredging up their past and their ghosts. She wants to explain how she sees him as the man who had sex with his ex-wife just because and rejected her for the second because he couldn't god damn wait and how he ran off with some busty blonde flight attendant when he wanted uncomplicated and how much she wishes she didn't see him in that way. She wants to explain how she wishes she could be more open for him, how she wishes that it were her that's uncomplicated, and how scared she is of losing him because of her own stupid boundaries.

They'll be gone, someday, those boundaries. The last parts of the wall. Smaller now. But they will be gone, someday soon, and she knows it- they'll all crumble. She's just scared he might not be around for when it does.

"I just don't want to lose you, Castle." She whispers instead.

Castle nods, solemn. "You won't lose me." He promises.

Kate grips his hand tighter, steps forward into his personal space and presses a palm to his chest. "You can't say things like that, Castle. Just look at what happened today."

He lets go of her hand to wrap his arms around her, tugs him to her and holds on tightly. Kate shudders and feels a few tears slip from her eyes, buries her face into his neck and sighs softly into his skin. Those three words rise to her lips again, but she swallows them back down. Not now. Not yet. She doesn't want those words to be forced from her because of this. She wants those words to come from her just because she loves him.

"You won't lose me." He repeats into her hair.

Her hands play with the hair on the nape of his neck. "I'm sorry, Castle. I'm sorry for these past few days, for doubting you, I- I'm sorry." She confesses into the skin of his neck, clutching him tightly and still feeling the fright of almost losing him running throughout her veins.

"It's okay." He whispers, stroking a hand through her hair. "We're okay, Kate."

And she believes him.