A/N: Wrote this fic years ago but somehow never got around to posting it on ff so here it is. Mistakes are all mine but the show isn't. Enjoy!

Set during S04E21 Headhunters

—-

"What the hell happened?" Beckett asks the moment Detective Slaughter starts leading Shea away to the interrogation room.

"You should have seen it," Castle starts gushing, "Slaughter got the drop on the one guy, but the other guy tried to make a break for it, I had to take his ass down."

Castle reaches into his pocket for a piece of tissue, removing the one wedged into his bloody nose as his partner looks on at him in disbelief. "What? Are you kidding me? You're a writer, Castle, not a cop."

"Yeah, I can take care of myself, you just never give me a chance," he points out, wishing the ringing in his head would stop. Or at the very least, tone down to a more bearable level.

Beckett fires back, "Yeah, because I'm not trying to get you killed." She may have a point there. Castle has a splitting headache from the bar fight earlier, and he probably should have gotten checked out by a medical officer, but Slaughter started on about interrogating the suspects and Castle had offered up the Twelfth.

"Castle, Castle! You still here with me?" Beckett's voice cuts through the ringing and for a moment, it becomes blissfully silent in Castle's head. He feels a wave of concern wash over him-

"Earth to Castle?" Beckett continues, waving her hand over his face. Castle shakes his head, snapping out of- whatever that was.

"I'm- fine. Just, hit my head earlier and I think I might have passed out? There's this ringing, it comes and goes, but I'm sure it'll be fine."

Beckett frowns at him, taking a small step forward. Castle instinctively takes a step back, keeping his distance from her. A stab of hurt washes over her face but is quickly replaced by concern. "Castle, it sounds like you might have a concussion."

"What? No, I'm sure it was just a light bump. Besides, Slaughter's really going to help me shake up this next Nikki Heat book."

Beckett crosses her arms in front of her chest and begins walking away. "Yeah, sure, if you live long enough to actually write about it."

Damnit Castle just what are you doing?

Castle stiffens and stares after Beckett's retreating back. He swears he's just heard her speak but it didn't sound like it came from her. It sounded like it came from inside his head.

—-

The ringing in Castle's head has tamed into a mild annoyance ever since his earlier encounter with Beckett. He didn't get the chance to ponder about it though, following Slaughter out of the interrogation room to chase their next lead, the Jamaicans.

As they walk past Beckett, Castle hears her voice inside his head again. This time, it is only one word.

Burke.

What does that even mean?

—-

It takes a while, but Castle begins to notice a pattern forming. The ringing sound in his head has completely disappeared – not a concussion, take that, Beckett! – but a minor headache forms whenever he's around the Twelfth. Or, well, he feels a sense of disappointment and sadness from… somewhere.

In the back of his mind, Castle suspects it might have something to do with Beckett, but she hurt him with her lies and he wasn't going back to her, damnit!

However, it doesn't matter anyway because Castle soon finds himself going back to her – like a moth to the flame – after seeing Slaughter coach a confession out a kid, implicating Valez and the Mexican gang for killing Glitch to incite a gang war between the Westies and the Jamaicans.

—-

Slaughter's confrontation with Beckett at the crime scene leaves a bitter taste in Castle's mouth.

Crap, what have I done? This is what I want, stepping up for Castle, maybe it's not too late to show him but- focus, Beckett.

"We've got about an hour to figure out who really killed Glitch before I get called up by the Chief of Detectives," Beckett says, aloud this time. There is definitely something weird going on because Castle swears he distinctly heard her in his head voice, and her normal speaking aloud voice.

Castle tries to keep his voice steady as he addresses what she said. "What can he do to you?"

Why is she talking about stepping up and being too late to show- what?

"Well, best case scenario he suspends me."

Castle feels dread building up deep in his gut as he asks his next question. "And the worst case scenario?"

Beckett remains silent, giving him a grim look but he hears her answer in his head anyway.

I lose my job but what do you care, you've got a blond stewardess and other cooler cops to shadow. I'm the idiot who took too long to heal and I've lost my chance anyway so Burke was a waste-

"Who's Burke?" Castle blurts out.

Beckett completely freezes as the blood drains from her face. "What are you talking about?"

"You just, keep… bringing him up. Burke, he's a, a person, right?" Castle stammers, realizing he's addressing something he heard inside his head.

Beckett stumbles back a step, her hand coming up to press against her sternum. Her bullet scar. "How do you- who told you?" her voice cracks with anguish, her eyes swimming in betrayal.

"No one told me anything," Castle tells her, raising both hands in supplication. "I uhh, I think I can hear your thoughts?"

Beckett starts rubbing against her scar as tears well up. Her voice wavers when she speaks. "Castle, it's not funny. Just- tell me. Who-"

"I'm sorry, I'm sorry," he cuts in, rushing forward to gather her in his arms, unable to bear the pain in her voice.

She's absolutely rigid in his arms, but Castle will not let go. He knows she's a hair away from a breakdown. Her panicked thoughts race around his head and Castle focuses on speaking to her to keep from intruding on those thoughts.

"It happened after the bar fight. You might be right, I think I got a concussion or something but for some reason I ended up being able to hear your thoughts when you're near me. I know it's a violation of your privacy, but I didn't even know what I was doing, or well, I couldn't confirm it until… just now. I'm sorry, Kate, I'm so sorry."

She pulls back from his embrace to look him in the eyes, two tracks of tears streaming down her face.

I swear, Castle, if this is a prank-

"It's not a prank," he answers, watching her eyes go wide. Castle rubs a hand down his face and sighs. "Actually, do you mind if we have a real conversation? I don't really know how this mind reading thing works yet and I don't want to accidentally uhh, intrude on your thoughts."

"How many-" she clears her throat, continuing, "Does it work on everyone?"

Castle gives her a half-hearted smile. "Only you, it seems."

She raises her eyebrows at that. "Lucky me. And uhh, what did you, what have you heard?"

Castle closes his eyes as shame and remorse well up to join his constant state of confusion ever since this thing began. "Something about stepping up and a blond stewardess, healing and taking too long, and, well, losing your chance? What are you talking about, Beckett?"

She pulls away from him then, breaking free of his embrace and he lets her go.

He sees it then.

"I've hurt you," he says.

His recent actions have been hurting her more than she's let on.

Beckett swallows, staring at her feet. "I thought, I thought we had a- we talked about my wall and you were supposed to- but you-"

"Kate," he says, the use of her first name causing her to look up at him, "what are you talking about?"

"You started pulling away, Castle, and I don't know why..."

You're hurting me and I don't even know what I did wrong, her accusation rings loud and clear in his head.

"You lied to me," he whispers. His voice carries anyway in the still night, his breath misting in the air and he sees her stiffen at his words. "The plaza bombing, I heard you in the box with Bobby Lopez. You remembered everything, you heard me and…"

Understanding dawns on her face then.

He watches the play of emotions across her face – sadness, guilt, relief, and finally, peace.

"Castle, when you said those words at the cemetery, I wasn't ready to hear them. And even after my recovery, I wasn't in a place to accept them or do anything about it, which is why I've been seeing Dr. Burke."

She pauses a moment to take a step forward. Now they're standing toe to toe. "He's been my therapist for the past seven months while I was healing and getting myself to a better place. To become a better person, Castle. For you." She licks her lips, her eyes darting up to catch his. "For us. So that we can have a real shot at this."

She barely leans forward to erase the space between them, sealing her lips over his.

I love you.

He melts into her kiss, one arm wrapping around her waist as the other cradles her head. She moans softly and he feels her satisfaction as a sensation inside his head.

When they break apart, both of them are sporting matching blissful grins.

"Let's solve this case, Castle. And then," she trails off, tugging on his hand.

"And then?"

He hears her answer loud and clear in his head.

I wanna fuck your brains out.