After a contestant in a beauty pageant is found strangled, many suspects turn up, including jealous fellow contestants, the pageant's sponsor (Michael McKean), and the show's host (Sasha Roiz).
Against orders, Beckett travels to Los Angeles while investigating her ex-partner's murder; Castle questions Beckett's motives.
Castle and Beckett investigate the death of a champion swimmer; authors Michael Connelly and Dennis Lehane give Castle advice.
When a reporter is found dead inside a pizza oven, Castle and Beckett try to determine why he was murdered.
A juror suddenly dies during a high-profile trial involving a murdered socialite.
When the head writer on a popular soap opera is killed with a fire axe, Castle is able to use his skills as an author to make a discovery about a killer.
Castle and Beckett must set aside their differences with Agent Fallon while trying to prevent a city-wide catastrophe.
While investigating an apparent robbery-homicide, Beckett and Castle discover the victim was involved in a mysterious conspiracy; as the stakes rise, a federal agent (Adrian Pasdar) takes over the case.
An old friend of Castle's emerges as the prime suspect in his wife's murder.
The murder of a lottery winner leaves Castle and Beckett with a wealth of suspects; Martha must decide what to do with her inheritance.
The retired lead detective on Beckett's mother's homicide case is gunned down after telling her he has new information; Castle and Beckett's partnership grows stronger.
The owner of a historic magic shop is found dead in Houdini's water torture tank; a new romance comes to light.
When Castle's novel Heat Wave becomes a movie, actress Natalie Rhodes accepts Beckett's invitation to visit and learn about the character she will play; Natalie observes Castle and Beckett's investigation of the murder of a matchmaker.
When a bar owner's body is found in the East River, the investigation takes Castle and Beckett through the forgotten tunnels and passageways of turn-of-the-century New York; Castle considers buying a bar.
When a prominent astrophysicist is found dead in her car, Castle is led to theorize her death was the result of an alien abduction.
While investigating a subway worker's murder in Central Park, Castle and Beckett unexpectedly uncover a boy's abduction.