A/N: Due to the accumulating number of additions and inserts I've written for 'Hiraeth' on Tumblr, I thought it might be a good idea to begin putting them all in one place that offers easier access. Each chapter will be a different insert or add-on (not including the Christmas addition, which can be found in chapter ten of 'In the Spirit') in no specific order and - because pieces of my heart are still rooted in this universe and the likelihood of it continuing is still alive - updates will be sporadic and posted whenever a new request is made.

Set any time after chapter six, when Beckett starts sleeping in Castle's bed.

She is rarely a deep sleeper to begin with, always ready for the buzz of a cell phone, the drop of a body, to wake her. But since he disappeared and she would crawl into bed praying for a phone call, she sleeps restlessly and anxious to wake. Since he's come back and she's returned to his bed, she sleeps even lighter, drifting along the edges of consciousness.

So when a nightmare has him twisting and turning beside her, Kate's eyes are already open and her hand is already reaching for him. He's had nightmares in the past, the curse of a writer's imagination plaguing him after a hours at his laptop or hours with her on a hard case, but she knows the bad dreams have become a far more frequent occurrence these days.

She touches her hand to his shoulder blade, fingertips scaling scars she still isn't familiar with beneath the damp t-shirt.

"Castle," she calls, clearing her throat when his name leaves it in a rasp. "Castle, wake up."

He rolls onto his back, mumbling incoherencies, his chest heaving with a fast heartbeat. Kate shifts to rise onto her elbow, lean over him, but when her fingers graze his throat, his entire body goes stiff. Castle's arm snaps up from his side, seizing her wrist in his grasp with impressive speed. Her lips part around his name once more, but he's up and rolling on top of her before she can speak it.

The weight of his body pins her to the mattress, knocks the breath out of her before she can gasp. His fingers curl around her wrists, hard enough to bruise, and she's reminded of his size, just how strong he truly is. One of her legs reflexively hitches to defend herself, but she stops before she can bring her knee to his groin.

Even though his eyes are open, he's staring down at her unseeing. Still asleep.

"Rick," she breathes, her own heart racing beneath his. She hates to imagine what he must be dreaming of to hold her down with such force, whom he's trying to subdue. "You're dreaming, Castle. You're with me."

His fingers twitch at her wrists, his lashes flutter, and Kate is able to slip a hand from his grasp, lift it to his cheek.

"Castle." One of her legs is trapped beneath his, but the other curls at his thigh, draws him down to her. Anchors him. "Hey, you're here with me. You're safe with me."

He blinks, his brow furrowing as his gaze clears, settles on her beneath him before flicking around the room to register his surroundings.

The tension drains from his body, from hers, and his grip on her wrist goes slack. She raises her other hand to his cheek, earns the slide of his gaze back to her face.

"Kate?" he whispers, the horror leaking into his eyes. "Shit, I - what did I do? Are you okay? Was I hurting you-"

"I'm fine," she promises, but he's shaking, his arms quivering as he tries not to collapse on top of her any more than he already has. He has that little boy look of terror written all over his face and it's breaking her heart.

Kate tightens the leg at his thigh, strokes her thumbs to his cheeks before she twines her arms around his neck, embracing him. His chest shudders and he sinks against her, slips his arms around her frame, and chokes out a broken noise into her shoulder.

"It's okay," she promises, even though it isn't. He isn't and she's scared for him, afraid of whatever put that terrified look on his face.

He's quiet for a long moment and she almost asks if he remembers the dream, if he can recall who had his heart galloping and his skin going damp, who he was seeing before the haze in his eyes dissipated for her.

She feels the heat of his breath against her clavicle, the drop of moisture seep through the sleeve of her shirt.

"I'm sorry," he rasps, but she shakes her head, resists the urge to tighten her arms around him.

"You were dreaming-"

"I could have hurt you," he groans, the shame in his voice all consuming. "I could have - maybe you shouldn't be in the bed with me, Kate. I couldn't handle it if I-"

"Rick, nothing happened," she insists, unable to stand the guilt that doesn't belong in his mouth.

"But I-"

"I'm not going anywhere." It comes out a little more forcefully than she meant it to, but it has him deflating with a sigh against her.

"Fine," he mumbles. "But just - wake me up, shake me or something, if it happens again."

"Almost kneed you," she admits, relishing the relief that floods her chest at the choked sound of his laughter.

"Thank you for sparing me, but if that's what it takes to-"

"I knew you wouldn't hurt me," she murmurs, brushing her thumb to the top of his vertebrae. "You woke up, Castle."

He doesn't say anything, releasing another sigh into her skin. She wants to tell him that it's okay, that it will be okay, but she knows it won't help, that the words are empty.

He's close enough for her to press her cheek to his, but Castle is already easing off of her, onto his side. She goes with him, lets him draw her into the cove of his body. She copies his position, pressing her forehead to his shoulder, sucking in a shallow breath of his scent, and unfurling her fingers at his back.

His scars are raised beneath her palms, meeting the tips of her fingers through the barrier of his t-shirt between them. She leaves her hands splayed across his spine, closes her eyes against his collarbone, and trains her breath to match his until the band of his arms slowly loosens and his chest rises and falls against hers without trouble.

She can't sleep like this, embraced so snug and warm, but she doesn't dare move. She doesn't want to.

Kate closes her eyes, allows her heart the rare indulgence of peace it's found since his return, encourages its beat to block out the low roar of panic that is constantly brewing in the back of her mind.

She's not back in this bed with him solely for his sake. She needs to be here, needs his body close and in reach, needs the reminder.

It's become the only way her heart will calm at night.