Just when it seemed that their entire relationship was on the line, Rick Castle stepped up, got down on one knee and asked Kate Beckett to marry him in Castle season 5 finale "

This is a photo of Gail O'Grady on Castle. It's from the episode "Reality Star Struck."

Beckett is faced with a number of big life decisions on "Watershed," the season five finale of Castle on ABC.

Tamala Jones is featured in this scene from the Castle Season 5 finale. She's checking out a crime scene.

The entire Castle scene is on the crime scene in this season five photo. It is from the finale.

Kate Beckett is not at all ugly. Check her out in this scene from the season five finale.

What's the good word? This is a scene from the Castle Season 5 closer, "Watershed."

Kate Beckett is in a panic in this scene from the Castle season five finale. It is titled "Watershed."

Castle and Beckett talk to Espo in this scene from Castle. It's courtesy of the Season 5 finale.

Castle clearly has a lot to ponder in this photo from "Watershed." It's the Season 5 finale.

Beckett and Castle have a lot to talk about in this scene from "Watershed." It's the Season 5 finale.

Carlos Bernard guest stars here as a mysterious government operative. This is a photo from the penultimate episode of the season.