'Castle' season 8 spoilers, news: Nathan Fillion reunites with Summer Glau in 'The G.D.S.'


The next episode of crime drama series “Castle” will see the reunion of former “Firefly” co-stars Nathan Fillion, who stars as mystery writer Richard Edgar Castle/Richard Alexander Rodgers in the ABC series, and Summer Glau, who guest stars as a private detective competing with Castle to solve a mysterious murder.

In 2002, Fillion and Glau starred in “Firefly,” the short-lived Joss Whedon-helmed space western drama series that only aired eleven episodes but received a 2003 Primetime Emmy and now enjoys a cult status among fans. Fillion, who plays the lead character in “Castle,” has frequently made homages to “Firefly” in the ABC series.

Glau, whose TV credits include “Alphas,” “Arrow,” and “Terminator: The Sarah Connor Chronicles,” is not the first of Fillion’s “Firefly” co-stars to pop up in “Castle.” “Suits” actress Gina Torres and “Chuck” actor Adam Baldwin have also appeared on the show. Recently, both Fillion and Glau appeared in an episode of “Con Man,” the web series helmed by fellow “Firefly” alum Alan Tudyk.

In “The G.D.S.,” Castle heads to Los Angeles to learn about what happened in the time that he cannot remember, but things take a dangerous turn when he is tasked by the Greatest Detective Society to try to solve a murder. Glau guest stars as private investigator Kendall Frost, a member of the secretive society, while TV legend Gerald McRaney guest stars as G.D.S. head Mason Wood.

According to TVLine, the upcoming episode’s storyline and guest star roster has raised speculation that ABC may be preparing for a “Castle” season 9 that does not include either Fillion or co-star Stana Katic (NYPD homicide detective Kate Beckett). The ABC Entertainment Group President at that time, Paul Lee, revealed that “there are a lot of conversations going on” about the future of “Castle,” though he did not specify in which direction the popular series could go.

“I don’t want to give a glimpse to what those ideas might be,” the now-former ABC boss said in the article, “but I’m feeling optimistic that we’ve got some good ideas.”

“Castle” airs Mondays at 10 p.m. EST on ABC.