Castle is disappointed when his plans to see a screening of Forbidden Planet are postponed thanks to his latest case. Joe McUsic, one of the jurors on the high-profile murder case of young socialite Lila Addison, has just died in the courtroom. Now that the case may go to mistrial, the defendant (Otis Williams) might receive a better chance. One of the other jurors mentioned that they were threatened by Otis's cousin, Wardell. Camera footage shows that Wardell gave Otis a cup of coffee, which may have contained enough cyanide to make Otis drop dead. Wardell claims that his cousin is innocent, and there's a conspiracy at work to frame him for the crime. DA Lou Karnacki is trying this case himself, which hints that the case may be more important than anyone realizes. Wardell is cleared of the crime when it's found out that the cyanide in Joe's body was from a time release capsule given to him before he arrived at the courthouse. Stranger still is the fact that Joe may have managed to buy his way onto the jury. The victim's brother, Stephen, insists that Lila didn't know Joe. Meanwhile DA Karnacki speaks with Captain Montgomery about making sure he knows all the details of Joe's murder investigation. Photos are found which show Joe at Lila's crime scene. However, Joe had an alibi during Lila's time of death. Ryan finds out that Joe got in touch with the DA, saying that he had evidence which would clear Otis's name. The conspiracy theory starts to make more sense, as it's discovered that Lila's parents donated heavily to the DA's election campaign. Otis says that someone else was driving the car the night Lila was killed, and the prints on the seat match Eddie's. Eddie knew the victim and her brother as thrill-seeking drug addicts. Eddie was helping them out on a drug run, and as their car hit a pothole, Stephen accidentally shot his sister. Eddie knew the siblings' family was rich, so he agreed to help cover up the shooting or else risk being framed for the murder himself. Eddie then told Joe the entire story, and how Otis was completely innocent. Joe decided that he'd get on the jury for the case in order to help clear Otis's name. He mailed evidence (Stephen's bloody clothes) to the DA's office. Meanwhile, Montgomery speaks with Karnacki. The DA promises him a job as the next Police Commissioner if he agrees to stop the investigation. The Captain respectfully says no. Later, Castle has discovered an app which allows him to see Alexis's whereabouts by keeping tabs on her phone. Alex is a little upset at this, then tells her father that her friends had shoplifted and that she went back to the store and paid for all the things they stole. However, she won't say who her friends are. Castle finally gets his classic sci-fi movie night, and he gets to share it with Beckett.