Season 4 - Episode 23 : Always May 7, 2012
Season 4 - Episode 23 : Always May 7, 2012
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.
Season 4 - Episode 22 : Undead Again Apr 30, 2012
When a dead man is found with human bite marks on his body, a witness claims the deceased was attacked by a zombie.
Season 4 - Episode 21 : Headhunters Apr 16, 2012
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.
Season 4 - Episode 20 : The Limey Apr 2, 2012
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.
Season 4 - Episode 19 : 47 Seconds Mar 26, 2012
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.
Season 4 - Episode 18 : A Dance With Death Mar 19, 2012
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.
Season 4 - Episode 17 : Once Upon a Crime Feb 27, 2012
When two women are found dead dressed as fairytale characters, Castle and Beckett must race to find the killer before he strikes again.
Season 4 - Episode 16 : Linchpin Feb 20, 2012
Beckett and Castle must stop a series of events that could result in a war.
Season 4 - Episode 15 : Pandora Feb 13, 2012
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.
Season 4 - Episode 14 : The Blue Butterfly Feb 6, 2012
Castle and Beckett must investigate a mysterious case from 1947 in order to solve the present-day murder of a treasure hunter.
Season 4 - Episode 13 : An Embarrassment of Bitches Jan 23, 2012
The investigation into the death of a famous dog trainer leads to a reality-TV star.
Season 4 - Episode 12 : Dial M for Mayor Jan 16, 2012
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.
Season 4 - Episode 11 : Till Death Do Us Part Jan 9, 2012
When Castle and Beckett investigate the death of a ladies' man, a twist in the case may disrupt Ryan's wedding.
Season 4 - Episode 10 : Cuffed Dec 5, 2011
Beckett and Castle wake up handcuffed together in bed in a locked room with no memory of how they got there.
Season 4 - Episode 9 : Kill Shot Nov 21, 2011
The team searches for a sniper who is terrorizing New York; Beckett tries to hide her worsening condition from Castle and the detectives.
Season 4 - Episode 8 : Heartbreak Hotel Nov 7, 2011
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.
Season 4 - Episode 7 : Cops & Robbers Oct 31, 2011
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).
Season 4 - Episode 6 : Demons Oct 24, 2011
Castle and Beckett investigate the murder of a ghost hunter who was looking into a haunting at a New York mansion.
Season 4 - Episode 5 : Eye of the Beholder Oct 17, 2011
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.
Season 4 - Episode 4 : Kick the Ballistics Oct 10, 2011
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.
Season 4 - Episode 3 : Head Case Oct 3, 2011
Castle and Beckett investigate a crime scene that involves a large pool of blood but no victim; Alexis receives news about Stanford.
Season 4 - Episode 2 : Heroes & Villains Sep 26, 2011
Castle and Beckett suspect a costume-clad vigilante is responsible for the mysterious murder of an ex-con.
Season 4 - Episode 1 : Rise Sep 19, 2011
Detective Beckett struggles to survive; Castle tries to identify the shooter; Ryan and Esposito try to adjust to the new captain.