It was a dull throbbing that woke Castle. A throbbing in his head that was reminiscent of a toothache in the way it wouldn't go away, but one that hurt every part of his head except his teeth. When he finally accepted that the pain wasn't going to fade no matter how much he tried to will it away, he opened his eyes, confused by the dreams he'd had and the aches that certainly seemed to be trying to tell him that something was wrong. The first thing he noticed – aside from the fact that he wasn't completely sure where he was – was that the side of his face and most of his neck and shoulder on that same side were also damp. He reached up and pulled away a towel and what might have been some kind of freezer bag or something similar. Whatever it was, the towel was soaked, and was probably the reason he was.

Castle had just realized that what he was holding might have been an icepack at one point when his stomach cramped abruptly and for a moment he thought he might throw up. Then his head cleared long enough for him to decide it wasn't nausea. He was hungry. He turned his head cautiously, trying to keep it from falling off, and saw that Kate Beckett was asleep in a chair that had been pulled closely up to the couch he found himself on. He stared at her, certain that he was seeing things, because he had no idea where she'd come from, and his befuddled brain couldn't come up with any scenario that could possibly have come to this conclusion.

He reached out his hand to touch her – mainly to prove to himself that she wasn't really there – and found that the arm he touched was very much real. Her eyes opened at the touch, and he read the concern in them before he managed to figure out that he was the cause of it.

"Castle?" She leaned over, taking the icepack from his hand, and her eyes met his as she ran her hand lightly over the side of his face. He tried to force a smile to clear the worry from her gaze but he must not have been too successful, because she frowned. "How do you feel?"

"Hung over…" he answered, and his voice croaked in the middle of the word. "My head hurts." He started to raise his hand to try and figure out why, but she stopped him before he could.

"You have a bad cut," she told him. "Try not to touch it."

"Where are we?"

"My apartment."

He frowned, looking around, but he realized that she was right; they were definitely in her living room. Which meant he was on her couch.

"What happened?" he asked. "How did we get here?"

"Do you remember anything from yesterday?" she asked.

He stared up at the ceiling, trying to think. The pain in his head, the ache in his stomach and the fact that his bladder was suddenly threatening to burst all seemed to be far more overwhelming than the fact that he couldn't remember arriving at her place. Then he saw a flash in his mind, a face that wasn't his, and a room that wasn't one he'd ever seen before. He tried to see the face again, but he couldn't get beyond the aches and pains to do it.

"I don't know," he admitted with a sigh of frustration. "It's all fuzzy. There's a room… and a guy – I think – and I couldn't reach my phone…"

He trailed off, annoyed that he couldn't remember the information he wanted, and anxious since he knew it was important that he did. He felt her hand on his arm and he turned to look at her and was surprised to see that she didn't look as annoyed as he felt. She looked more concerned than anything.

"How's your head?"

"What? It hurts."

His stomach growled, loudly, and she must have heard it because she smiled.

"When's the last time you ate anything, Castle?"

He shook his head.

"I don't know."

"Then if you're up for it, let's take care of the distractions, first," she suggested. "Maybe it'll help you remember if you're feeling better…"

That made sense to him. He started to sit up a little more, and she moved quickly to help him. Assistance that he needed, he was chagrined to find out. His entire body was one giant ache and his muscles were all stiff. He groaned when they finally got him upright, and he put his head in his hands, carefully avoiding the spots that hurt the most.

"I feel awful," he told her, not looking up.

"Well, if it helps, you look awful, too."

"Thanks."

He heard a soft chuckle.

"Do you want a painkiller? There are still a few here."

"Do you have any aspirin?"

The last thing he wanted was to lose what little grasp he had on reality, and he'd already figured out that he didn't do that well under the influence of potent medications.

"Sure."

"So you don't know how I got here?" he asked, looking up as she got up to go get him the pills.

"You were here when I came home."

"Huh…" He took the aspirin from her with a soft thank you and downed them. "Did I break in?"

"You used your key," she told him. "Think you can eat anything?"

He had the impression that she was going to try and go at his memory loss obliquely instead of head on. He'd seen her use the technique with witnesses before – ask them questions in random order to get answers that didn't make them thing too hard about anything and maybe get in the way of what they were trying to remember – and he was more than willing to go along with it.

"I could eat anything," he assured her. "But I really need the bathroom…"

"Need help?"

"No, I got…" he trailed off with a grunt of pain when he tried to stand, and she helped him up and steadied him while he tested his balance. The headache was making everything else impossible. "Maybe a little help…?" he asked, his hand bracing on her shoulder.

Beckett smiled, and shifted until his arm was over her shoulder and she was supporting more of his weight than he'd originally intended.

"Okay?"

"Yeah."

They moved slowly, but eventually she got him as far as the door to the bathroom. Beyond that he was determined he could do things on his own, and he was fairly certain she'd prefer it that way, too. She left him standing at the door and brought over a stack of clothes that he recognized as his own.

"Esposito brought these over. You'll probably feel better if you're dressed."

He didn't know for sure that he agreed, but it certainly wouldn't hurt.

"Thank you."

She smiled.

"I'll make breakfast while you get yourself cleaned up a little. Be careful, though, not to hurt yourself, and call me if you need help."

He allowed an eyebrow to rise, even though it hurt to do it, and was rewarded with a blush and a half smile. She didn't say anything, though, she just made sure he was steady enough on his feet to be able to take care of himself, and then she left him and headed for the kitchen.

Castle grinned, already feeling a little better – although it might have been because his head wasn't pounding quite so badly – and he headed into the bathroom.