A/N: so I've read quite a few post-ep fics for this particular episode, but I wanted to write one myself. Enjoy :)

"Detective Beckett, Mr Castle," Gates said, coming out of her office, "go home, get some rest and take tomorrow off if you need it. Goodness knows you deserve it."

"Thank you, Sir, but I'm sure I'll be fine once I've had a good nights sleep." Beckett replied. Good nights sleep? Not likely after the day she'd had. To think that less than 24 hours earlier she was about to persuade Castle to go with her favourite font for their save the date cards.

Castle and Beckett stood up to leave, Javi and Ryan stopping them to double check Beckett was okay.

"Mr Castle, a word?" Gates said quietly, heading back into her office.

Castle followed her, feeling slightly confused. "Can I help you, Sir?" He asked.

"Look, you know Beckett better than most and you know how stubborn she is." Castle nodded. He'd never met anyone as stubborn as Kate Beckett. "But I'm worried about her. I know she can look after herself and she's one of the strongest women I've ever met, but today was tough. Tougher than anyone could have imagined..I'm still angry at what I sent her in to..I mean if-"

"Captain, you can't blame yourself, this isn't your fault. I know without a doubt that if you had known the severity of the situation, you never would have sent her into it in the first place."

Gates gave him a tight lipped smile. "You're right, Mr Castle, thank you." She said. "I can tell how much you love her and it's written all over her face how much she loves you, but I just want to make sure you're there for her for the next few days. As much as I hate to admit it, you're good for her and I know she won't be able to get through this without your love and support."

Castle smiled. There was a compliment in there somewhere, he was sure of it. "Thank you, Captain, but I have no intention of letting her out of my sight for the foreseeable future. The rest of my life if she'll let me."

Gates laughed. "Yes well, go..take her home and remind her why she's lucky to have you."

Before Castle could get back out to get Beckett and take her home, he was accosted by Esposito. "Bro, there's something I need to give you."

"Right now? Surely it can wait?" Castle just wanted to take his fiancé home and make sure she really was okay. She'd put up all her walls around everyone else, but he was the one person she would let in. He knew for a fact that he wouldn't know she was completely okay until her got her alone.

"Here, take this." Esposito said, shoving a piece of paper into Castle's hand. "CSU scrubbed the place where Beckett said they took her, looking for anything that would tie back to Simmons but this was all they found. It's addressed to you." He said, walking away.

Castle looked down at the paper he'd just been given. Espo was right - his name was written clearly on the front. He had a feeling he knew what it was, but he wasn't going to look now, not here.

Walking over to where Ryan was giving Beckett another hug, he whispered, "hey, you ready to go?" In her ear.

"Yeah, I am." She said, smiling up at him.

"Good." He replied. Saying one last goodbye to the boys, they stepped into the elevator, Beckett wrapped into his side.

"Come to bed?" Castle said, placing his hand in front of her. She hesitated for a minute, but took his hand eventually, leaving the smiling face of the man behind her mothers murder on the screen.

Shuffling down under the covers, Beckett pressed herself as close to Castle as she could, completely wrapped up in his arms. "I was so scared, Castle. I thought I was never gonna see you again." She whispered into his chest.

"Hey," Castle soothed, "come on, you should know by now you wouldn't be able to get rid of me that easily!" He said, his humour just what she needed right now. It was one of the things she loved about him.

"I meant what I said, the only thing getting me through that..that torture was you. I had to get back to see you, it was the only thing keeping me going."

Castle didn't reply, he just hugged her tighter. It broke his heart thinking about what she had been though today but he knew what she meant about thinking she was never going to see him again, he'd felt exactly the same about her.

"You were with me the whole time, Castle, you never left." She said. He could feel her tears starting to soak his shirt.

"Oh Kate, sweetheart," he said, rocking her back and forth slightly to try and calm her down. "I'm glad I could help, even if it was just in your mind." It killed him knowing he wasn't actually there, he'd felt so helpless at the precinct, not being able to do anything to get her back to him.

"I love you." She whispered.

"I love you too, Kate, god I love you so much, don't you ever forget that." He said into her hair.

He held her like that for the next ten minutes until she eventually passed out from exhaustion. He knew Kate though, knew she'd probably be awake in less than an hour, quite possibly from a nightmare. And he'd be here, he'd hold her and tell her she was safe until she fell back into a fitful sleep. It was all he could do and he had to hope it would be enough.

Thirty minutes later and it was clear to Castle that he wasn't going to get any sleep. Every time he came close to drifting off, he had to double check Kate was still sleeping next him. Suddenly, he remembered the paper Esposito had given him as they left the precinct. Slipping out of bed carefully so he didn't wake Kate, he retrieved the paper from his pocket and climbed back into bed again. Opening it up, he read;

"Dear Rick, I don't know how much time I have, even to write this letter. What I do know now, is that I'm in this and the only way I'm gonna make it out alive is to see this through. I'm sure everyone is looking for me and if they figure out I was here, CSU is gonna search this house. They're gonna look for blood and they will find it. Which will lead them to this letter. Babe, it's your letter and I hope you never have to read this and I can tell you all of these things in person. But if something happens and I don't make it, I need you to know that our partnership, our relationship is the greatest thing that has ever happened to me. You're an amazing man and I love you with all of my heart. Always."

"Oh god, Kate." He whispered as he finished reading her letter to him, his tears flowing freely down his face. His poor Kate. She'd been stuck there with no way out and she'd thought of him. She'd written him the most beautiful letter and he'd been at the precinct not being able to do anything to help her.

"No..no, don't touch me!" Kate shouted in her sleep.

Castle checked the time. She'd only been asleep for 45 minutes and the nightmares had already got to her.

"Kate..hey, sweetheart, wake up." He shook her gently, wanting her to wake up but not wanting to startle her.

"No..get off me!" She cried.

"Kate..Beckett, honey, come on, wake up." He shook her slightly harder, desperate to end this torture she was going through.

"Castle..oh god, Castle.." Castle thought she must have woken up and realised she was safe, but then she spoke again, "no..I want..Castle. Need..Castle.." His heart broke into a million pieces, she wanted him but she thought she couldn't have him.

"Kate, I'm here, it's me, I'm right here..wake up." Suddenly her eyes flew open and she screamed in terror.


"I'm here, baby, I'm right here." He said, pulling her close to him once more. "It's okay, you're safe."

Kate took a few deep breaths and calmed down. "Thank you." She whispered reaching up to brush her fingers over his face. "Why..why are you crying?" She asked. "Oh god, did I hurt you? Oh Castle, I'm sorry-"

"No Kate, you didn't hurt me, oh god no, I'm fine, sweetheart, I promise." He kissed her softly.

She sat up next to him. "Then why are you-" she broke off as her eyes darted across to the piece of paper he'd been reading. "Oh. You um, you read it."

"Yeah, I did." He said, sitting up next to her and wrapping his arms around her. "I can't believe you wrote that Kate, it's..oh god it's beautiful. I mean I wish you hadn't been in a situation where you'd even thought about writing something like that..but I'm glad I read it."

"I meant every single word Richard Castle, don't you ever doubt how much I love you."

"I won't, Kate. I promise." He whispered back to her.

"I know I tried doing everything I could do to push you away but I've never been so happy that you stayed as I was today. I mean it, you're the most incredible, wonderful, amazing man I've ever met and and I'm the luckiest girl in the world to be able to call you mine."

"Oh god Kate, I wouldn't have left, I couldn't. I love you too much, always have." He said, planting a kiss on the top of her head. "Sweetie, you're soaked." He said a few minutes later. "That nightmare must have been awful, you're sweating through your shirt."

"It's your shirt, Rick." She mumbled into his chest and he laughed.

"Yes, you're right." She'd insisted on wearing something that smelt like him to bed tonight. "Come on, let's get you in the shower and then back to bed."

"'Kay." She said.

Five minutes later and Castle had divested them both of their clothes and had the hot water running, steam billowing around the bathroom.

Opening the door of the shower, Castle waited for Beckett to get in first. "What's wrong?" He asked when she didn't move. "Kate, what is it?"

"I uh..I can't do this." She whispered and it hit him. Her hair had been wet when they found her, they must have dunked her into water or something. Son of a bitch. If he ever got anywhere near Vulcon Simmons, he would personally make sure he paid for what he'd done to Kate.

"Hey, look at me. Kate, look at me." She raised her head half an inch to look at him from under her lashes. "Baby, you're safe, okay. You're with me, okay, you're safe. I won't let anything hurt you."

She nodded, taking small steps towards the shower. Taking a deep breath, she stepped in, grabbing Castle by the had as she did,making sure he was still there. "I'm here baby, I promise." He whispered. "You're doing great, okay. Just take it slow and you'll be fine." Stepping forward another inch, Castle eased in behind her and closed the door. Finally, she took the plunge and stood under the stream of water.

"You did it!" Castle said, "I'm so proud of you, Kate, come here." He pulled her close, both of them standing under the water together.

"Thank you." She whispered.

"Always, Kate, always."

Fifteen minutes later and Castle had managed to give Kate a quick wash and wrap her up in a towel. Finding another one of his shirts for her to wear, he dressed them both and wrapped her back in his arms in bed.

"I love you." She mumbled into his chest as she fell asleep. "So much.."

A/N: this is the first time I've ever written a post-ep fic, how did I do?! This wasn't really how I planned it going, but the words just sort of came out! I'm sure many people are much better at it than me, but your thoughts would be appreciated :)