An astrophysicists’ body is found in her car, the cause of death is explosive decompression. Castle jokes that she was killed in outer space, and soon the team’s evidence all leads to high-tech space gear, a mysterious government agent who tries to stop the investigation, and, ironically, alien abductions. What happens when “Castle” goes sci-fi?

Castle goes with the boys to a casino where a murder took place. He also hopes to throw a party foe Ryan. Beckett stays back with Captain Gates to work a case with her. Gates wants to see if Beckett can handle the case without her "distraction". We will see.

Castle follows (Nathan Fillion) as Richard Castle, a famous mystery novelist who has killed off his main character in his book series and has writer's block. He is brought in by the NYPD for questioning regarding a copy-cat murder based on one of his novels. He is intrigued by this new window into crime and murder, and uses his connections to charm his way into shadowing the captivating Detective Kate Beckett, played by (Stana Katic). Castle decides to use Beckett as the model for the main character of his next book series starring "Nikki Heat". Beckett, an avid reader of Castle's books, initially disapproves of having Castle shadow her on her cases, but later warms up and recognizes Castle as a useful resource in her team's investigations.