"Castle" Season 6 started with Kate Beckett accepting Rick Castle's marriage proposal. We do get a hint of the upcoming wedding once in a while but there has been no actual scene that provides a glimpse of wedding planning. It will be fun watching Beckett planning the wedding with Castle and Esposito and Ryan chipping in their ideas.

In the previous episode, Castle and Beckett were unable to go shopping for their wedding because Alexis needed Castle's help to set free a death row inmate. Alexis believed that the inmate was innocent. Despite being mad at her father, she sought his help to prove the man's innocence, and Castle agreed to do that, though he had his apprehensions. Castle and Alexis were able to solve the case right before the inmate's execution. At the end of the previous episode, Alexis became less mad at her father and she thanked and hugged Beckett for her help. Can we now expect Beckett and Castle to go shopping for their wedding?

The preview video suggests that another murder mystery is going to keep the two love-birds occupied. The episode eight of "Castle" Season 6 is called "A Murder is Forever." Beckett and Castle have to solve the murder of a famous relationship therapist. At first, it looks like the murder happened because of diamond, which is likely to have a price tag of millions of millions dollars. But, Castle soon realises that the murder of the relationship therapist has more to it than just for the diamond.

 [Youtube/becklebee9nfsk3]

Official Synopsis of "Castle" Season 6 Episode 8, "A Murder is Forever": "When a famed relationship therapist is murdered, it appears that her access to the secrets of her elite and powerful clients led to her death. But when Castle and Beckett discover the victim was in possession of a rare object worth millions of dollars, they realize that this case may be even more complicated - and dangerous - than they thought."

Chad Gomez Creasey and Dara Resnik Creasey have written "A Murder is Forever, while Bill Roe has directed the episode.