Ep 14. The Blue Butterfly

In the Castle season 4 episode 14, titled "The Blue Butterfly," Richard Castle and Kate Beckett are transported back to 1947 as they investigate a case involving a murdered antique dealer and a rare blue butterfly brooch.

The episode begins with Castle and Beckett attending an auction at a museum where they encounter a mysterious woman who panics and drops a blue butterfly brooch before running away. Later that night, they receive a call from Captain Montgomery informing them that the same woman has been found murdered, and the brooch is missing.

As they begin their investigation, Castle and Beckett find themselves transported back to 1947 through an old elevator in the museum. They are surprised to see that everyone around them is dressed in period clothing and that the museum is hosting an exhibit featuring rare and priceless artifacts from around the world.

They quickly realize that they have been sent back in time to solve the murder of the woman they had encountered earlier and to locate the missing blue butterfly brooch. They team up with a private investigator named Harry and the curator of the museum, who also happens to be the victim's sister.

As they start unraveling the clues, they discover that the victim had stolen the butterfly brooch from the museum, and she was planning to sell it to a wealthy businessman. The investigation takes them to various locations around the city, including a high-end club, an antique store, and a pawn shop.

Throughout the episode, Castle and Beckett struggle to adapt to a world that is vastly different from their own. They must navigate their way through a society where women are treated differently, and racial tensions are high. They even find themselves in a dangerous situation when they encounter a group of men who don't take kindly to their presence.

Despite the challenges, they manage to solve the case and find the missing brooch, but not without being transported back to the present just in time to avoid getting caught up in a deadly explosion.

"The Blue Butterfly" is a unique and enjoyable episode of Castle that transports the audience back in time while still maintaining the show's lighthearted and humorous tone. The writing and directing are exceptional, and the acting is top-notch, with Nathan Fillion and Stana Katic delivering standout performances. The episode is a must-watch for fans of the show and anyone who enjoys a good murder mystery with a time-travel twist.