During its four seasons run, the show had many wonderful and amazing guests, including a few of “The L Word” alumnae. Laurel Holloman played a wife of a murder victim in the first episode of season two. Anne Ramsay also appeared in season two as one of the suspects in the murder of a young rock star. Dana Delany, who was a guest star on “The L Word” as a seductive senator, participated in an explosive two-part episode in season two, where she played an FBI agent, assigned to Beckett’s unit in a search of a serial killer.

Anne Ramsay on “Castle”

The two-part episodes or ‘events’, as Nathan Fillion calls them, are a special treat on the show. Those episodes are usually focused around some major events that in the end always manage to bring Castle and Beckett closer together. Season two brought us a hunt for a serial killer who was infatuated with Nikki Heat, a character that Castle created based on Detective Beckett. In season three it was a search for a dirty bomb intended to destroy New York City until the dynamic duo found and disarmed it.