Ryan sent Jenny to her mother's.

Esposito tried the same thing with Lanie. His back-up plan? He sent her to a spa.

Castle's mother sent herself away, and took Alexis with her after a little prodding.

So they were all safe. There was only one love left to worry about.

Castle just stared at Kate for a few minutes. For a second, she looked so vulnerable, as if a stray wind could blow her away. She couldn't possibly survive a dirty bomb. He relived the fear from when she said she had been exposed to radiation. As usual, she was in the middle of this. He couldn't send her away. He couldn't protect her.

Funny how the one woman who made him feel like he could do anything was also the only one who could make him feel this helpless.