|Episode Online Video|
S03, E16 (First Aired:
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.
S03, E17 (First Aired:
Castle and Beckett must set aside their differences with Agent Fallon (Adrian Pasdar) while trying to prevent a city-wide catastrophe.
S03, E19 (First Aired:
A juror suddenly dies during a high-profile trial involving a murdered socialite.
S03, E20 (First Aired:
When a reporter is found dead inside a pizza oven, Castle and Beckett try to determine why he was murdered.
S03, E21 (First Aired:
Castle and Beckett investigate the death of a champion swimmer; authors Michael Connelly and Dennis Lehane give Castle advice.
S03, E22 (First Aired:
Against orders, Beckett travels to Los Angeles while investigating her ex-partner's murder; Castle questions Beckett's motives.
S03, E23 (First Aired:
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).
S03, E24 (First Aired:
A professional hit man (Max Martini) with information about the murder of Beckett's mother escapes during a court hearing; Castle and the team uncover a deep conspiracy.
S04, E01 (First Aired:
Detective Beckett struggles to survive; Castle tries to identify the shooter; Ryan and Esposito try to adjust to the new captain.
S04, E02 (First Aired:
Castle and Beckett suspect a costume-clad vigilante is responsible for the mysterious murder of an ex-con.
S04, E03 (First Aired:
Castle and Beckett investigate a crime scene that involves a large pool of blood but no victim; Alexis receives news about Stanford.
S04, E04 (First Aired:
When a young woman is shot to death, Beckett and Castle learn the gun used was the one a serial killer stole from Detective Ryan.
S04, E05 (First Aired:
A sexy insurance investigator (Kristin Lehman) with a secret helps Castle and Beckett when a valuable sculpture is stolen and someone is murdered; a rich museum benefactor (Jessica Tuck) garners suspicion.
S04, E06 (First Aired:
Castle and Beckett investigate the murder of a ghost hunter who was looking into a haunting at a New York mansion.
S04, E07 (First Aired:
Martha and Castle are held hostage by bank robbers dressed in hospital scrubs; Beckett's rescue efforts are hindered by a strict hostage negotiator (Dean Norris).
S04, E08 (First Aired:
When a casino owner is murdered at an abandoned warehouse, suspects emerge in New York and Atlantic City; during the investigation, Castle throws an impromptu bachelor party for Ryan.
S04, E09 (First Aired:
The team searches for a sniper who is terrorizing New York; Beckett tries to hide her worsening condition from Castle and the detectives.
S04, E10 (First Aired:
Beckett and Castle wake up handcuffed together in bed in a locked room with no memory of how they got there.
S04, E11 (First Aired:
When Castle and Beckett investigate the death of a ladies' man, a twist in the case may disrupt Ryan's wedding.
S04, E12 (First Aired:
When a woman is found dead in her car, the investigation leads to New York Mayor Robert Weldon (Derek Webster), one of Castle's longtime friends.
S04, E13 (First Aired:
The investigation into the death of a famous dog trainer leads to a reality-TV star.
S04, E14 (First Aired:
Castle and Beckett must investigate a mysterious case from 1947 in order to solve the present-day murder of a treasure hunter.
S04, E17 (First Aired:
When two women are found dead dressed as fairytale characters, Castle and Beckett must race to find the killer before he strikes again.
S04, E15 (First Aired:
Castle and Beckett discover that the killer they are pursuing is part of an international conspiracy, and they must work with a CIA agent with whom Castle has a history.
S04, E18 (First Aired:
The investigation into the death of a contestant on a popular dance competition show leads Castle and Beckett to a shocking secret that may have led to her death.
S04, E19 (First Aired:
When a bomb kills five people at a protest rally, Beckett and Castle try to solve the case by reconstructing the 47 seconds prior to the explosion.
S04, E20 (First Aired:
An attractive detective from Scotland Yard (Brett Tucker) teams up with Castle and Beckett to investigate the murder of his friend's daughter; Lanie tries to talk Beckett into making a move on Castle.
S04, E21 (First Aired:
Castle takes on Detective Ethan Slaughter (Adam Baldwin) as his partner when tension between himself and Beckett rises, and he sees a new side to police work that puts him in danger.
S04, E22 (First Aired:
When a dead man is found with human bite marks on his body, a witness claims the deceased was attacked by a zombie.
S04, E23 (First Aired:
Castle tries to protect Beckett as she pursues the man who shot her; the 12th precinct is forever changed as feelings and secrets are revealed.
S05, E01 (First Aired:
Castle and Beckett set aside questions about their relationship in order to take on the forces responsible for the murder of Beckett's mother.
S05, E02 (First Aired:
On Beckett's first day back from suspension, she and Castle investigate a weathercaster's death, and try to hide their relationship from their co-workers.
S05, E03 (First Aired:
When a woman is murdered, Castle and Beckett think a repossessed storage unit may have a connection to her death.
S05, E04 (First Aired:
Castle's plans with Beckett are disrupted when a dying man stumbles into his backyard and collapses in his pool.
S05, E05 (First Aired:
The investigation into a ritualistic murder turns up evidence linking Castle to the crime, leading Beckett to wonder how well she really knows him.
S05, E06 (First Aired:
As Beckett and Castle investigate a murder at a sci-fi convention, they encounter avid fans in costume, egotistical celebrities and a lot of drama.
S05, E07 (First Aired:
A documentary crew follows Castle, Beckett and the team as they investigate the murder of a rock band's lead guitarist.
S05, E08 (First Aired:
While retrieving a murder witness, Castle and Beckett are ambushed, forcing them to take the witness on the run.
S05, E09 (First Aired:
Castle and Beckett investigate when a bearded man named Kriss Kringle falls from the sky in Central Park; Beckett and Castle work on a Christmas list together.
S05, E10 (First Aired:
Several angry ex-husbands come under suspicion when a divorce attorney who only represented women is murdered; when Alexis gets sick, Castle's ex-wife moves into the loft to take care of her.