"Castle" Season 6 Episode 21, titled "Law and Boarder" will feature the murder of a professional skateboarder. Castle and Beckett will be seen trying to find the mysterious motorcyclist who gunned down the skateboarder.

In the preview clip, Castle can be seen suspecting someone who could have used his skills in extreme sports to kill the up-and-coming skateboarder. The synopsis of the episode suggests that the world of extreme sports is hiding something more dangerous than what is assumed by Beckett and Castle.

[Youtube/TV Promo]

The highlight of the episode is expected to be a game of scrabble between Castle and Beckett. The sneak peek of "Law and Boarder" provides a glimpse of the game, which Castle loses to Beckett. He can be seen sulking at the end of the game.

[Youtube/Becklebee CastleVitalScenes]

In the sneak peek, Castle and Beckett can be seen at the work place, and Castle asks Beckett if she is ready to go home and hoping that she is not tired. The two are shown playing a game of scrabble. Castle is keeping the scores and it looks like Beckett is one losing the game. Beckett wants to quit and concede, and suggests that they can do something more important. Castle insists that they complete the game and Beckett feel the "bitter sting" of defeat.

Beckett's quixotic makes her the winner. She says sorry to Castle, as he seems to be in complete shock. The bitter sting of defeat makes Castle want to be alone. It is likely that this scene will lead to Castle and Beckett talking about the next issue on their wedding preparation list.

Official Synopsis of "Castle" Season 6, Episode 21: "Law and Boarder": "When an up-and-coming professional skateboarder is gunned down by a mysterious motorcyclist, Castle and Beckett are thrust into the world of extreme sports, where the death defying stunts aren't the only thing that's dangerous."

Jim Adler has written the episode, while Tom Wright has directed it.