The last time she walks in on them nearly paralyzes her, because he's down on one knee and definitely isn't tying his shoe or picking something up.

Kate isn't crying or anything schmaltzy like that, but Castle has a huge goofy grin on his face and the longer she stands there, the bigger it grows, until he actually giggles.

She'd seen the ring in his briefcase the week before and had put it out of her mind until that minute, watching it glint in the box that sat in his hand.

"Dad?" she asks, stepping the rest of the way into the dining room. He jumps like someone has kicked him and runs across the room and pull her into a hug that practically cracks her ribs.

"She said yes!" he laughs and his happiness stuns her; though she was used to his boyish giddyness, this is a true and real joy that she was unfamiliar with.

Over his shoulder, she catches Kate's eye, who smiles with the tiniest hint of trepidation, like she's waiting for Alexis's approval before celebrating.

So Alexis smiles back and nods the tiniest bit.

Kate grins back.