In the Castle episode “G.D.S.,” when in Los Angeles, Castle (Nathan Fillion) is asked to meet with the head of the legendary Greatest Detective Society (G.D.S.), Mason Wood. Wood asks Castle to look into the murder of Philip Harris, a private investigator who was working on the lot of a Hollywood studio at the time of his death.
GDS head Mason Wood is portrayed by Gerald McRaney. He’s best known for his roles on House of Cards (Raymond Tusk), Mike & Molly (Captain Patrick Murphy), Deadwood (George Hearst), Major Dad (Maj. John “Mac” McGillis), and Simon & Simon (Rick Simon). He most recently starred in the TNT series Agent X with Sharon Stone and in the TV movie Coat of Many Colors (he played Dolly Parton’s granddaddy). Castle airs Mondays at 10pm on CBS.