A manhunt is launched for professional hitman, Hal Lockwood, after he escapes during a court hearing. Lockwood possesses information about the murder of Beckett's mother. As the hunt proceeds, Castle and the team find there's someone with connections to law enforcement who's linked both to the death of Johanna Beckett and to Lockwood's escape. The season finale leads to a highly emotional and deadly conclusion with the search for Lockwood and his co-conspirator.moreless
Castle and Beckett investigate the murder of Miss Illinois, a contestant in a beauty pageant, who was found strangled during the rehearsal for "Baron's All-American Beauty Pageant." As the investigation goes on, they find out that several people had motive to kill the victim.
When Beckett travels to L.A. against orders, with Castle, to solve the murder of her ex-partner, Castle questions her motives. Meanwhile, they get to meet the actors who will be portraying Esposito and Ryan in the film adaptation of Castle's first novel 'Heat Wave'.
Castle and Beckett must solve the murder of a champion swimmer who had a shot at the Olympics. They need to sort through all the secrets they uncover to find what led to his death. Meanwhile, Castle's poker buddies offer their views on the case.
When a reporter is found dead inside a restaurant's pizza oven, Beckett and Castle go to work on solving the case. They must figure out if his story "The Pizza Wars" is what got him killed or if there's something more to the story.
When a juror dies in the middle of a murder trial, Castle and Beckett discover that the juror wasn't really as perfect as he appeared to be.
Castle and Beckett investigate the axe murder of the head writer for a long time New York soap opera. Everyone is suspect when it's discovered that the action behind the scenes plays out as good as the on-air story lines. Castle uses his writer's skills to figure out who's the killer.moreless
Castle and Beckett must work together with Agent Fallon to prevent a momentous tragic event that could affect the entire city.
Castle and Beckett investigate what it seems to be a robbery-homicide, but while investigating the case they find out that the victim was involved in a mysterious conspiracy.
Castle and Beckett investigate a murder in which the prime suspect is one of Castle's old friends.
Castle and Beckett investigate the murder of a lottery winner, leaving them with plenty of suspects to look into. Meanwhile, Martha inherits money she feels she doesn't deserve.
Castle and Beckett investigate the murder of the lead detective on Beckett's mother's homicide case.
Castle and Beckett investigate the murder of the owner of a historic magic shop found dead in a Houdini's water torture tank. Meanwhile, Lanie and Esposito are trying to keep their relationship secret and Castle ends his relationship with Gina.
When Castle's novel "Heat Wave" is turned into a movie, actress Natalie Rhodes, shows up at Beckett's invitation to better understand the character she's going to play. Meanwhile, the threesome investigate the murder of a high-class matchmaker.
Castle and Beckett investigate the murder of a dockworker turned bar owner whose body is found floating in the East River. In the process of the investigation they uncover a secret buried since the days of Prohibition.
Castle's latest theory is alien abduction after an astrophysicist's death is found to be from explosive decompression. A well known alien abduction expert gets involved in the case. To complicate things more, a government agent wants to shut down their investigation.
Castle and Beckett investigate the murder of an NYC subway worker found shot in Central Park. But, while investigating the murder they uncover the abduction of a young boy as well. The team must determine the motives behind the high stakes kidnapping in order to save the young boy's life.
An "Officer Down" call turns out to be a male stripper dressed like a cop. Castle and Beckett explore the world of male strip clubs and struggling actors, all people in pursuit of fame. They need to determine if the murder was because of the victim's dreams of stardom or something more sinister.moreless
A dead woman leaves clues indicating that the Tripler Killer aka 3XK is back after a four year hiatus. Castle and Beckett play a deadly game of wits with the killer to prevent more killings.
When pallbearers lose control of a casket at a funeral, the deceased and a second unknown woman tumble out of the casket. The victim turns out to be a doctor at County Hospital. Now it's up to Beckett and Castle to determine if the world of bed-hopping physicians created murderous jealousy or if the doctor's work outside of the hospital got her killed. Gina attempt to bond with Alexis puts a strain on her relationship with Castle.moreless
Castle and Beckett investigate the murder of a young mathematician killed with a 200-year-old bullet, this makes Castle's imagination roll giving out some crazy ideas about a time-travel killer.
With the latest case of a murdered bail bondsman, Beckett discovers that Castle's wild imagination and theories may be on the mark. Beckett's ex-partner makes a surprise arrival and Castle is forced to watch the two reminisce and engage in a little romance.
Beckett and Castle look for the killer of a famous psychic while debating whether extrasensory abilities are real or not. When a letter arrives from the victim predicting her death they must determine who actually wrote the letter – the victim or the killer.
Beckett and her team burst into an apartment on a murderer's trail, just to be surprised when they see Castle, who they haven't heard or seen in months, standing over a dead woman's body holding a gun. Beckett, has no other choice but to arrest Castle until he proves his innocence.moreless