Kate's hand is tight in his as they step out of Agent Stephens's suburban together, the gravel driveway crunching beneath their feet. Castle sucks in a breath at the sight of the cabin in the woods, nestled deep amidst the trees.

They're in Connecticut, not New York like he assumed. Northeast and near a river that Stephens theorizes Castle eventually escaped to.

"We found an abandoned motor boat that washed up on the coast of New Jersey. It'd been reported stolen over a month ago, around the time of Rick's re-emergence, and it had a dinghy attached to it," the agent explained to them on the drive over. Castle had been unable to fathom how he got from Connecticut to the coast of Delaware. "It matched the description of the one you were found in. My guess is that you took the motor boat as far as it would go and continued in the smaller boat until you eventually passed out from what I presume was exhaustion. The current was reported strong that night, probably just carried you from there, left you adrift for at least a day."

It isn't that Castle doesn't believe the plausible assumption - Stephens is likely spot on - he just wants to remember it all for himself.

"I'll wait out here for you guys," Stephens tells them, cutting the engine. "Local cops came by to unlock the place earlier, so take as long as you need."

Beckett murmurs her thanks in response, but Castle's gaze is still trained on that god-forsaken little cabin. So innocent looking, lonely even, but inside is his own personal hell.

"Still okay?" Kate asks at his side, her thumb brushing along his knuckles. He glances down to see her watching him, the bruise that colored one side of her forehead from the car crash two weeks ago almost completely gone, most of the residual horror that clung to her eyes from that night now receded.

The decision to accept Stephens's offer to finally see Castle's place of captivity wasn't an easy one and for the first week, he simply put it out of his mind. He focused solely on his physical recovery, on Kate's, on going to therapy twice a week with her and Lily. It wasn't until Burke brought it up in their second session, his individual one, that he even began to consider it, allowed his curiosity to get the best of him.

No matter how severely it terrifies him.

So they contacted Stephens, planned an early morning trip with every intention of returning to the city by midday, despite not needing to pick up Lily from school today. Tom Demming is taking her to their favorite smoothie place and then for soccer in the park, something they apparently bonded over years ago.

It still nags at him, but Tom was there for Lily during the years that Castle couldn't be. The other man adores Lily as if she's his own, and jealousy aside, Rick can't help but be grateful for the positive presence Demming has been in his daughter's life.

Kate sways into his side and he flexes his fingers, tangles them with hers.

"Still okay," he confirms with a nod, squeezing her hand and offering her his best attempt at a reassuring smile, one he's sure falls flat.

But Kate lets him take the lead, following as he guides them up the short path of the driveway, onto the porch steps that creak and groan beneath their weight. She waits patiently as he hesitates at the front door.

It's just a house, small, unremarkable and not well-kept by any means. The people who made the place feel so evil are gone, dead, and can't hurt him anymore.

Castle curls his hand around the knob, pushes the door open to reveal a surprisingly normal-looking home. Not that he expected chains and whips to line the walls, but it's… unsettling, picturing Tyson and Nieman so casually existing here while he was in one of these rooms somewhere, suffering.

Kate remains close to his back as he steps inside, roams his eyes over the living room. The mismatched furniture is worn with age, the fireplace against the wall layered in dust, and the wallpaper is peeling, faded and featuring a pattern of mallard ducks.

"I never spent any time here," he murmurs. His gaze is cast along the kitchen that merges with the modest living area in the cabin's open floor plan, unaltered in decades. It makes him wonder how anyone would willingly stay here, so secluded and cut off from the rest of the world, but that was exactly what Tyson and Nieman wanted, wasn't it?

"She must have grown up here," Kate mumbles, nodding towards the mantle. There are scattered framed photos showing a young redhead with an older man and woman, each shot posed and stiff.

"An unhappy childhood, I'm sure," he mutters, suddenly eager to get out of this space where Kelly Nieman still exists so heavily.

Castle starts towards the hallway that sits between the kitchen and living room, checking each door that lines the length of the short corridor, revealing a bathroom and two normal bedrooms. But the fourth door leads to a larger room which lacks a bed, dresser, any personal touches.

A wooden desk consumes most of the space instead, pieces of technical equipment littering the surface, a computer propped up in the middle.

"The speakers in my room," he realizes aloud, releasing Kate's hand to take a closer look, but not touching anything. "This must have been where Tyson talked to me, where they watched me, always knew what I was doing and when I would try to escape."

He can practically envision the view of his room on the computer's dark monitor, can remember all of the hours he spent glaring at that tiny, blinking light of the camera in the corner across from his bed. How he attempted to knock both it and the speakers down on multiple occasions and how he was punished for it.

"Castle, were you ever… treated here?" Kate inquires. He turns away from the monitoring equipment, sees her examining a small cot pushed up against the wall, stains of blood on the white sheet pulled taut across the top.

The scars on his back flicker with phantom pain.

You should know better than to defy him.

Castle pinches the bridge of his nose between his thumb and forefinger as his first clear memory of Nieman pierces through his skull.

"Once," he chokes out, earning the flash of Beckett's gaze.

In that moment, he regrets what he's about to tell her, regrets bringing her here. She looks so much healthier, her skin tinted with far more color, the hollows of her cheeks a little fuller, and the blue of her shirt bringing out the golds and greens in her eyes. He doesn't want to douse them in darkness, but she's waiting on him, on edge and impatient to know. She wants everything and he promised to give it to her.

Too late to go back on that now.

"He had - Tyson, I'd made him mad. Close to the end. He used the whip, went too far, then tried to strangle me with it. She made him stop."

He remembers now, being dragged into the house by the both of them, being dropped on his stomach atop that little cot against the wall near the door where Kate stands now. Nieman treated his wounds to stop the blood loss, to keep him alive.

"A year and a half ago, I think," he offers, time having become such an ambiguous thing. That's at least how old Doctor Xanders presumed the deepest of the scars on his back to be, and he knows the worst were born from this incident.

It was his first time being outside again, seeing the open sky and the branches of trees trembling overhead, feeling the dirt beneath his feet and the air in his lungs. It revived him.

"It was what I needed."

Her head jerks towards him at that, her eyes on fire and wide with horror. He holds up his hand in supplication.

"I was giving up, pushed Tyson on purpose, hoping he'd just… kill me already," he confesses, and he has to watch her heart break, crack across her face. Her arms band around her body in a habit that he hates, and it makes him want to cross the distance between them, hold her until it dissipates. But he needs to get this out. "It had been so long and I was starting to forget what the outside meant to me, what it still held. Alexis's smile, the sound of your voice, it - the marriage announcement in the paper had a picture of you and I managed to keep it, it helped me remember even though that hurt, but I just… I wasn't getting out of there. And I knew it."

Kate wipes a hand over her eyes, glares down at the cot and squares her jaw. Fuck, this is even harder than he anticipated, worse than he imagined.

"But when they had to bring me in here, it was my first time out of that damn room, Kate." He sees her press the tips of her fingers to her mouth, her eyes dry, but she just looks so broken, broken for him. Maybe they shouldn't have come, maybe he should have come alone, maybe she should go back to the car.

But no, she insisted that they do this together, that she wasn't letting him go through any of it alone.

Castle covers the space between them, steals one of her hands from its coiled place at her ribs.

"It reminded me that there was still a world outside, one I wanted to get back to." Her eyes flicker up to meet his, glossy and raging like the sea, grief and fury swirling in her gaze. He thoughtlessly grazes his thumb along her naked ring finger. "It reminded me how much I wanted to get back to this, to you."

Kate tugs on their tangled hands, shaking hers free to wrap both of her arms around his torso, hugging him tight, and his breath catches unexpectedly. Because he can't count how many times he imagined this very moment here, the privilege of holding her again, the warmth of her body in his arms and the scent of her hair in his nose. How he clung to the memory of her to get through each endless day.

"Castle, you said you had to be taken outside," she murmurs, her voice thoughtful and her head lifting. "And we've walked through the entirety of the house."

He straightens with understanding, glances back over his shoulder to the computer screen.

"I was somewhere else. And… they had to drag me through the kitchen, not the living room, to get me in here," he recalls aloud, that memory hazy due to his tormented body, the pain steadily overtaking his brain. But the whine of the backdoor resounds in his mind and- "Backyard."

Kate steps back, ready to let him go first. Still, he reclaims her hand, starts for the exit with her at his side.

Kate follows him through the back door just off the kitchen, her heart still thick and in her throat over everything he's told her. The things he remembered in those few minutes, the look on his face and the way his voice cracked as he recalled how badly he wanted Tyson to kill him. She can't blame him, would never fault him for that, but the idea that she came so close to losing him for good, for real, without even knowing, causes her chest to clench and burn.

And all while she was off getting married-

"I think this has to be it," he says after they've circled the perimeter of the home, dragging her attention back to the present. Castle is standing in front of a storm cellar with rotting wooden doors and a raised cement outline. "It was always cool where I was, clammy. I just thought it had to be a basement, but this makes more sense."

He bends forward to tug on the chains and padlock looped through the handles of the doors, but they fall loose, already unlocked. Kate moves to help him, easing one of the brittle doors open while Castle pulls back the other. The smell of damp concrete rises to greet them, like rain on sidewalks, and Castle takes an immediate step back. He turns his face away from the ominous black entrance, the stone steps that lead down to more darkness.

She doesn't speak, doesn't want to push despite the concern building through her bones and the instinctive urge to ask questions, to know. But his moment of revolt is brief and he exhales slowly before returning his gaze to the cellar's entrance.

"If you want to wait up here-"

"No," she gets out, ensuring that none of the trepidation churning through her guts is showing on her face when he glances back to her. She hopes she looks stronger than she feels. She needs to know where he was for the last six years, needs to see it. If he can survive for six years in a storm cellar, she can survive a few more minutes down there with him. "I'm with you. Unless you want to go in alone, then I can-"

"No." Castle shakes his head. "I just don't want to - to hurt you with this."

"Rick," she calls, curling her fingers at his elbow. She presses into his side and he leans into the contact, visibly grateful for it. It reminds her of his needs, his sometimes desperate desire for physical comfort. "Don't worry about me. This is… brutal, but I'll be fine."

He doesn't necessarily look convinced, but he sways into her, touches his lips to her temple. He lingers there for only a moment before he pulls back, redirects his attention to the storm cellar.

"Better get it over with then," he exhales, steeling himself with another deep breath and following the first step down, the next. Kate goes in after him, descending into the darkness with the glare of sunlight at their backs.

It provides enough illumination for them to make it to the bottom of the stairs without issue and she watches Castle feel along the cold walls until he encounters a light switch. It brings a single fluorescent panel flickering to life overhead, casting a sickly blue glow throughout the room.

She blinks to adjust to the dim setting, but Castle seems accustomed to it already. She tries to ignore the way that cleaves through her chest.

"This is it," he breathes, his eyes roaming the cell. It has a dome-like ceiling and thick, steel pipe running along the length of it, with cords of rope hanging from the beam. The sight of that rope sabotages her, her breath her lungs threatening to collapse.

But Castle isn't even looking at the rope. He instead moves towards the bed attached to the wall, sturdy links of chain keeping the thin mattress in place a few feet above the ground, a thin, disheveled sheet strung across it.

The fluorescent shines directly above the bed and she watches Castle hesitate for a moment beneath it before leaning over the tiny mattress. He eases a hand underneath the bed's edge, comes away with a slim piece of paper.

"They never found it," he whispers.

Kate finally unsticks her feet from the bottom step, the low heels of her boots echoing loudly. The paper in his hand is worn and limp, a newspaper article the size of his palm.

"He gave it to me to torment me," he says, his thumb sweeping over the square image of her face. It's the same picture they used when her shooting at Montgomery's funeral made all of the local papers. Her eyes fall shut in revulsion. "And it kind of was, knowing what it was pertaining to, but… it was the first time I'd seen your face in over four years."

Kate steps in close behind him, drops her forehead to the back of his shoulder.

"I'm so sorry," she rasps. "Four years and I - I never should have stopped looking. I could have found you, I could have-"

"Kate," he grinds out, reaching back to squeeze her hip. She stays there with her forehead sealed to his shoulder and her tears leaking into his shirt. "Stop it. We've talked about this. You're a damn good detective, but you never would have found me. No one would have found me."

She chokes out an unbidden sob at the acceptance in his voice, bites down hard on her bottom lip to stop any more from breaking free. Castle brushes his thumb to her hipbone.

"You didn't do anything wrong," he says a little softer. She eases one of her arms around him, along his chest, and hooks her fingers over the rounded bone of his shoulder, keeps her other pressed between her chest and his back. "You had to think about Lily above all else and I'm glad you did. Look how perfect she turned out; that's all because of you."

Kate huffs, kisses his shoulder blade even as her head shakes in protest.

"I'm serious, Kate. Stop trying to take any blame for this, for anything. There was nothing you could have done."

She finally peels herself from his back, lets his arm circle her waist and reel her into his side.

"That makes it worse," she admits on a breath, swiping at her cheek and resting her forehead to his jaw. But her eyes are open, trained on the floor, catching the faded crimson specks staining the concrete, dried drops of his blood. Kate lifts her head to look up at him, one of her hands to his throat to drape her fingers at the steady beat of his pulse. "Knowing there's nothing I could've done to help you, to find you. Yet you were never dead to me, Castle. You couldn't be."

One of his arms loops at her neck, aiding the other at her waist in gathering her against his chest, mending some of the torn and aching pieces inside of her. She lets her cheek rest against the middle of the sternum, closes her eyes to the horror this room holds, and clings to the knowledge that Tyson and Nieman didn't win, didn't break him, keep him from her. Their demons are dead and they're standing damaged but whole in a place where Castle was once a prisoner.

He's free now, able to walk out the second he chooses.

"That's what kept me going, Beckett," he breathes against the crown of her head, loosening his arms around her. Kate tilts her head back to see his face, following the drift of his eyes around the room, the way they linger on the ropes overhead, the camera attached to the corner They snag there, unable to move on, and he doesn't finish the thought.

She waits him out, seeing memory building in his gaze like a spark trying to catch fire.

"That night I escaped," he starts, his voice dropping to that faraway tone he sometimes adopts unconsciously, drifting with his mind as his arms slip from her frame. "It was a storm, a really bad storm, and the red light went dark."

"The power went out," she clarifies on a breath. He nods dumbly, roves the walls with his eyes.

"The only way I could ever tell when it rained was when the water would start to seep along the walls. It's too hard to hear it down here, but that night, the thunder was so loud, it felt like it was shaking the ground," he recounts, his gaze flicking to his bed. "I never knew what time it was, night or day, but it felt late. It was one of the rare times I was just lying in the bed, not tied up, because Nieman - she'd been making Tyson give me those injections that week and they made me so tired."

"Injections?" she echoes, her chest tightening with a dread that has become an all too familiar companion.

"To make me forget. Tyson mentioned it when he took me a couple of weeks ago, an experimental drug, but she got it wrong and - and that night, as soon as I saw that red light go dead, I ran up the stairs, rammed my shoulder into the door until it finally broke open," he reveals. His skin shivers and she wonders if he's remembering the rain on his flesh, the harsh winds in the air, the strike of lightning and crash of thunder all around him. "I just kept running. I don't know which one of them shot me, but I remember running through the trees, the rain, not stopping, not even feeling the bullet."

Her palm splays instinctively at his side, protectively, just below his ribs. His bones rise and fall beneath her touch.

"And - yeah, yeah, Stephens is right," he whispers, his eyes aflame with the memories now, overflowing with them. "I ended up at the river, found a dock, a boat, the keys in the ignition. I didn't think, just took it and didn't stop. All I could think about was distance, putting as much of it between me and them, this place. I didn't even know where I was going."

Castle's eyes flash back to her, his hands gripping at her waist.

"I remember, Kate. I think I remember all of it now." His face is clear as he stands straighter. "I was pointing that boat towards the city, towards you. I just wanted to get back to you."