The next episode of "Castle" season 8 titled "The GDS" takes Rick to the City of Angels. Of course, it does not have anything to do with the glitz and glamour at all as Rick flies there hoping that he could make sense of the unexplained months that he went off the radar.

In the previous "Castle" season 8 episode, Rick recollected flickers of memories about his disappearance that were revealed to have something to Koreatown in Los Angeles.

While he had his plan all set in his head, fate had a different, not to mention more dangerous, plan for the mystery writer. A mysterious murder in Hollywood sends the legendary group of brains called Great Detective Society seeking his help.

This crime, however, also throws him face to face with another detective to be played by Summer Glau. The appearance of the "Arrow" star in the series had many pop culture fanatics excited as it will sort of be a mini "Firefly" reunion in "Castle" season 8.

For the uninitiated, "Firefly" is a space Western drama series that ran in 2002. It was directed by Joss Whedon and only aired 14 episodes. In 2003, the transitory show was awarded an Emmy. It has earned a cult status ever since. "Castle" lead star Nathan Fillion and Glau both starred in it.

In "Castle," Fillion's character often sneaks in "Firefly" references. The actor is best known for the epic series as he was the protagonist in it (Mal Reynolds) and writers often throw allusions of it in some of Fillion's lines. Glau, on other hand, played the role of River Tam in "Firefly."

In this "Castle" season 8 episode, however, she plays the role of a detective who will try to outdistance Castle in solving the mystery behind the murder of a victim at the Hollywood Love Cemetery. This could possibly be the reason why Castle's life will be on the line as he goes about the case.

"Castle" season 8 episode 14 "The GDS" airs March 7 at 10 p.m. ET on ABC.