As he begins his new job as squad commander, Sipowicz disobeys orders and keeps a murder investigation open... even though a Japanese man with diplomatic immunity has confessed to the crime.

Simone's recovery is hampered by a chest infection. The doctors differ in their opinions of which treatment to use. Sipowicz's ex-wife turns up at the station, drunk and asking for his help.

After a shooting at a bar, Simone and Sipowicz are sent to the hospital and find that they know one of the victims. The whole squad is involved in the hunt for the killers.

The child of a rich family goes missing. The father suspects Israel, a local vagrant, of kidnapping him. Sipowicz has other ideas. In another case, a jewish girl is found raped and murdered on a bridge. Later, a young woman is caught using the murdered girl's credit card. Medavoy, Martinez and Russell piece together the information.

A murdered boy's father insists that a homeless man is guilty. The mother takes Russell into her confidence. Simone and Sipowicz hunt the killer.

A woman is found beaten to death and left in a wooden crate. Simone and Sipowicz trace her family. Medavoy and Kirkendall hunt for the shooter of a Car Services worker. Russell is called to the hospital, where a 6-year old boy has died. His parents claim it was an accident.

A mother and 5 year-old child have been shot dead in their apartment. Simone and Sipowicz suspect that a previous break-in may be connected to the killings and that ADA Cohen might be able to help them find the killer. Russell and Kirkendall search for a missing child and trace known paedophiles in their hunt for the abductor. Sipowicz's doctor gives him some good news and good advice.

As Simone's condition worsens, Lt. Fancy makes a request to the Uniformed Officers to be aware of the need for a usable heart. Simone's colleagues have to occupy their minds with the case of an old lady found hacked to pieces in her apartment. Of her two sons, one doesn't seem to care about it and the other is too full of drugs to understand what has happened. Sipowicz's mood gets him into a fight.

New squad member, Danny Sorenson, arrives and gets sent to a drive-by shooting, with Sipowicz. The rest of the squad, including Russell on her first day back at work, attend another shooting. The two incidents are related and cause friction between the two teams of investigators. ADA Costas asks Sipowicz to look into an old case she has reservations about.

Officer Dornan disrupts an AA meeting, leaving Sipowicz no option but to involve Lt. Fancy. Dolores' father threatens to take action against Malcolm Cullinan and gets PAA Irvine into trouble. Sipowicz and Sorenson search for the pusher who supplied Mike Roberts. ADA Cohen continues to express his jealousy, over Kirkendall.

Mike Shannon brings in a young boy who makes a confession to Sorenson. Sipowicz worries about his up-coming court appearance facing Sinclair. ADA Costas takes care of him. Dolores father attends the court hearing.

Sipowicz stays away from the squad and tries to come to terms with his loss. Evidence comes to light implicating Cullinan in more misdeeds and Sorenson turns to Sipowicz for advice. John Irvine is released from hospital, but is reluctant to return to the Precinct.

Sipowicz is taken hostage in an interrogation room by a suspect in the murder of a pot dealer and two of her friends; a suburban mom found with drugs in her purse appears to be covering for her son.

When another woman is murdered by the serial killer, the detectives arrest a suspect... and discover the killer's identity; and expecting a baby, Sipowicz and McDowell decide to get married.

A man armed with a bomb walks into the station house and handcuffs himself to McDowell; unless the detectives release a Russian mobster from jail in one hour, the bomb will detonate.

Andy's off-duty and slightly underhanded work to prove that Hatcher killed his own wife lands him a transfer out of the 15th precinct and into the Bellevue Morgue engineered by Detective Hatcher. Meanwhile, the squad is up to their whips and chains after a dominatrix is found murdered.

A face from Clark's past makes an unwelcome return, while the key suspect in Andy's 18-year-old murder case turns up, face down. Jones helps Michael prepare to take the stand against his own father for killing his mom, and a man fears that his wife is going to lose her head after he loses her pricey necklace.

There's a new boss who comes from IAD with a mandate to clean up the squad. Andy receives a dead rat in the mail. John is heading off the rails. A doctor is found dead, and linked to a man who had a sex change.

The detectives tie the death of a pregnant woman to an adoption scam; Medavoy and Jones interview a woman who claims a masked assailant stole her valuable ring; and someone poisons Sipowicz's beloved fish.

While investigating a random stabbing, Sipowicz becomes obsessed with his own mortality after he's nearly gunned down by a murder suspect; Medavoy takes a job as a bouncer.

While investigating a murder, Sipowicz discovers a secret about Bale; and Ortiz and Murphy investigate a shooting tied to a talented up-and-coming basketball player.

A call-girl's death is linked to other murders involving women who'd gone through rehab; Ortiz and Murphy investigate the death of an artist who'd been carrying on an affair with a wealthy man married to two other women.

The detectives continue their search for a serial killer who targets alcoholics trying to get sober; and Clark and Jones investigate a homicide linked to a woman with whom Clark had a one-night stand.

The detectives investigate the smothering death of an elderly man married to a voluptuous woman in her 20s; and a state judge pressures Medavoy and Jones to find out who poisoned her mother.

A squad member is shot while storming an apartment; Clark and Jones investigate the bludgeoning death of a woman whose wealthy husband was going to finance a friend's salon business.