NYPD Blue (season 12)

Detective Laura Murphy joins the squad. A new Lieutenant, Thomas Bale, formerly of Internal Affairs, takes command from Sergeant Gibson. Someone sends Sipowicz a dead rat. Ortiz and Murphy investigate the murder of a homeless man while the rest of the squad work the murder of a doctor who is in town to research a book. Clark obviously still hasn't gotten over Devlin's suicide.

• Bonnie Somerville makes her first appearance as a Detective Laura Murphy
• Currie Graham makes his first appearance as a Lieutenant Thomas Bale. Graham had appeared in a different, supporting role in Season 4's "Emission Impossible".

Bale announces his mandate from the department to make the "rogue" 15th squad reflect "today's policing" and insists on micromanaging the details of every case, which causes friction with the detectives. Cases include a dead 8-months pregnant woman in a dumpster and a push-in robbery. Investigation of the pregnant woman's death exposes an adoption scam. Andy and John Clark's relationship continues to deteriorate as John struggles to cope with Devlin's death and his father's suicide. Andy's stalker poisons the fish in Andy's squad room tank.

• Mackenzie Phillips guest stars as Lorraine Stuval

A young woman is found bludgeoned to death in her closet. A man reports his son has been kidnapped. During the murder trial of Steve McClintock, who is accused of murdering a pregnant woman ("Fish Out of Water") Clark's testimony is impeached when he admits to having sex with Carly, McClintock's girlfriend and co-defendant. Andy's stalker orders child porn with Andy's credit card, which brings a visit from the FBI. A police mechanic finds a bug in Andy's police car. John Irvin traces the manufacturer of the bug, enabling Andy to hunt for his stalker, which Bale tacitly approves. Following a lead developed by Medavoy, detectives find that the kidnapping was staged by the victim, and his conspirators killed his girlfriend, who was the young woman in the closet.

• John de Lancie guest stars as Scott Garvin

Andy attempts to pull a drunken John Clark from a bar and is shot by an unseen assailant. When he returns to the squad the next day, three AA "friends" confront him based on an anonymous tip they received and Andy has difficulty making them believe he had not been drinking. The bar's bouncer provides Ortiz and Murphy information about John's behavior at the bar, which doesn't concur with John's version. Medavoy finds out Hatcher's detective agency did a credit check on Andy. Andy confronts Stan and threatens to kill him if he doesn't stop stalking Andy. Hatcher recorded the conversation and reports the threats to the police department. Bale reluctantly brokers a deal with Hatcher's uncle, the deputy chief for personnel, who agrees that Andy will not be charged with any crimes in exchange for Hatcher's banishment to a private security job in Miami. Clark receives a verbal reprimand from Bale. Bale also tears into Andy because of the influence Bale had to expend to save Andy's career. Clark quietly asks Andy if they can stay partners and Andy agrees.

• Jonah Hill guest stars as a store clerk

After being brought up short by both Bale and Baldwin, Clark reassesses his recent behavior and makes a tentative move to mend fences with Sipowicz. A man is stabbed while riding the bus with his family. A video store clerk is stabbed by a robber. A wealthy antiques dealer reports a suspicious burglary. Medavoy takes a part-time job as bouncer at a bar. Andy has a surprise visitor who helps him gain perspective.

• Jimmy Smits makes an uncredited (to maintain a surprise) appearance as the spirit of Bobby Simone
• Dennis Christopher guest stars as Mr. Prosser

While investigating closeted gay men who have been beaten and robbed, Andy finds Bale's credit card in the suspect's home. Andy returns the card to Bale and says he has no intention of looking into the matter any further, prompting a change in Bale's demeanor toward the detectives. A respected attorney is shot to death in his car. Ortiz and Murphy investigate a drive-by shooting at a basketball court. Clark accompanies A.D.A. Munson to a party honoring a lecherous judge. Greg and Bridgid have a lunch date.

• Chad Allen guest stars as Kyle Tanner
• David Garrison guest stars as Russell

A young pregnant woman is murdered, and the detectives find that the father is a bigamist whose two families hold the key to solving the case. Attractive young women who had just begun attending Alcoholics Anonymous meetings are being killed. Andy leads the squad in an undercover investigation to find the killer. Greg helps Bridgid close a sale.

• Corbin Bernsen guest stars as Bob Cavanaugh

Ortiz and Murphy go undercover to catch the AA killer. Steve McClintock is found stabbed to death in his apartment, which is full of steroids. The investigation leads Clark to Steve's girlfriend Carly, the witness with whom Clark previously had sex. Steve's killer claims Carly set up Steve to be robbed, but that Steve was not supposed to be home. Clark believes Carly arranged things so that Steve would be killed, but is unable to prove it, though Carly confesses to setting up the robbery. Bale informs Andy unofficially that he has passed the sergeant's exam.

• Sasha Mitchell guest stars as Darian Lasalle

Bale is hospitalized and his temporary replacement is more interested in playing golf than running the detective squad. When a young Muslim bride is found stabbed to death, Ortiz and Murphy suspect her husband. Sipowicz, Clark, and Jones arrest the man who shot Bale. Bale reveals he is permanently disabled and recommends to the chief of detectives that Sipowicz take over as the commander of the detective squad. At the celebration that includes Medavoy's retirement, the chief of detectives gives Andy the chance to make the case for why he should be the new squad commander and agrees to give him the job.

• Natasha Alam guest stars as Elena