Castle watched Kate watching Alexis walk away. Kate's doctor excused himself shortly after, promising the nurse would be in to move Kate to a room for the night. The silence stretched uncomfortably. Castle shifted on his feet and looked at the door.

"Could you stay for awhile?" Kate was staring at her lap, hands loosely wrapped around the thin hospital blanket.

"Of course." Castle pulled a chair closer to her bed and started fidgeting with the pen and pad of paper from the nearby table. "What should we talk about? I could tell you about Mother's latest escapades with-"

"Who are we?" Castle looked up at Kate with a deer-in-the-headlights expression, eyes wide and mouth slightly open. "I mean, who are we to each other? It's been bugging me. My memory is like Swiss cheese, nothing's in the right order and I can tell I'm missing important things. You haven't left my side since I fell. Your kid is practically kidnapping me to your place tomorrow. We're more than partners, aren't we?"

"That's complicated."

"I remember what I felt like when you kissed me." Kate's whispered comment stopped Castle's nervous fidgeting as he stared at her.

"What do you remember?"

"I felt hopeful. Happy. And at the same time, I remember being terrified, but I can't figure out why. It doesn't feel like the fear was related to the kiss." Kate stole a glance up at Castle through her eyelashes, face still safely tilted down.

"It wasn't a real kiss." Kate's head snapped up.

"What? Yes, it was. I very clearly remember that it was a real kiss."

Castle sighed and set the pen and paper back on the table.

"No, Kate. It wasn't. We were trying to sneak up to a building and we needed the guard to think we were a happy, drunk, non-threatening couple as we walked closer to him. But he wasn't buying our drunken stagger, so I kissed you to sell the role. You broke the kiss when you decked the guy."

Kate was silent for a minute, trying to figure out why she felt like crying as she returned to staring down at her hands. She wanted to ask another question, to ask about the memory of his voice saying that he loved her, but she was afraid to breathe around the lump in her throat. She knew that if she tried, a sob might escape.

The heart monitor's beep increased pace while Kate struggled to hide her emotions. Castle's eyes flicked up to it for a moment before he reached over and captured the hands she was staring at.

"Kate... I don't know what to say to make it better. Believe me, I wish I did. You and I have never been romantically involved, though I think there were a couple of times when we came close to starting. All of this will make more sense as more of your memories come back. You just need to give yourself some time."

Kate continued to sit silently, concentrating on breathing and feeling his palms on the backs of her hands. He started to sit back and she flipped her hands over to keep him from pulling away.

"Kate."

She said nothing, clinging to his hands and trying to breathe normally as the heart monitor beeped quietly, announcing to everyone in the room that she wasn't as calm as she was trying to be.

"Just... Don't leave." Her voice broke and she stopped speaking one word early, but she repeated it in her head like a mantra. Don't leave me.

"Okay, I'll stay." Castle tugged one hand free so he could lower the bed railing and scoot his chair all the way up to the bed. Kate rolled carefully onto her side facing him, still refusing to look up at him. She closed her eyes for a moment and sighed.

"I'm so tired..."

Castle squeezed her hand and brushed a strand of hair behind her ear.

"That's okay. Take a nap. I'll wake you if you need to be awake later."