Sipowicz suspects a private investigator of bilking a father for the past six months in a scheme to find the man's runaway daughter. Meanwhile, Kelly and Sharon LaSalle investigate the shooting death of a 13-year-old boy and try to apprehend the gang member responsible. But when the killer escapes from the precinct, and injures LaSall in doing so, Kelly and the other detectives must try to stop the murdered boy's father who plans to go after apprehends the killer himself. Also, LaSalle has a chance to move out of the precinct and into a more regular routine of detective work in which she takes the offer and leaves the 15th Precint for good.

Martinez investigates a baby that was killed in a car from an apparent drive-by shooting. Meanwhile, Lois Snyder contacts Sipowicz for help because a policeman that she was entertaining died in a compromising position and he moves the body to a less conspicuous location. Lesniak's ex-boyfriend, Officer Abruzzo, keeps showing up at the precinct and harassing her, while at the same time, Lesniak locks horns with the officious Vince Gotelli over his working skills and his racy items he keeps. Kelly's future with the department is decided when Internal Affairs comes to the precinct to re-investigate some of his old cases and the result is Haverill transferring Kelly to borough dispatch duty. But Kelly decides to quit the force and after saying goodbye to Sipowitz, he throws in his badge for good.

Simone and Sipowicz suspect a chiropractor of murdering his wife. A woman whom Simone knows finds her 11-year-old son in possession of a gun. Meanwhile, Medavoy tells Donna that he has changed to a high-fiber diet a part of yet another change in his life. While moonlighting as a security guard for Mike Roberts, Martinez becomes attracted to Leticia, a college student he's been assigned to protect and she's worried about her possessive father, a Colombian businessman who may have criminal connections.

Lesniak deals with a perpetrator and his "high priced lawyer and shrink" when he repeats the offense. Meanwhile, Detective Solomon uses a fast pull to take a possible serial killer case away from Simone after he brings in a possible suspect. One of Fancy's old contacts, Vinnie Greco, brings in a tip about a couple of guys looking for some heavy arms to do an armored car job and Sipowicz works with him, but Greco is working for someone else against Fancy. Sipowicz invites Andy Jr. over at his place for dinner where his son tells him that he is joining the Air Force. Also, Sipowicz proposes marriage to Sylvia and this time, she accepts.

Simone and Sipowicz investigate the race-related murder of a Puerto Rican teenager who was attacked while spray painting graffiti in Little Italy. Meanwhile, Medavoy meets Donna's former boyfriend, Harold, when he comes to the station to file a car vandalism report, while Donna makes a tough decision about her relationship with Medavoy. Also, Sylvia is mugged and she later tells Sipowicz a secret from her past about being raped as a teen.

Lesniak's preference of her lesbianism quickly gets around the precinct, which gives her mixed reactions. Meanwhile, Sipowicz clashes with Simone throughout their investigation of the senseless murder of two kids, which is only the start of a really bad day which also includes Sipowicz dealing with Sylvia's morning sickness, and Simone dealing with Russell who falls off the wagon.

Donna and Simone give Lesniak and Martinez advice, respectively, on their plans for their first date and night together. Afterward, Simone and Sipowicz investigate the death of a young woman who was brutally murdered in her apartment and Simone and Martinez travel to Atlantic City to apprehend their suspect. Meanwhile, Medavoy and Russell try to find the perps who shot a wealthy and shallow surgeon during a mugging, and they also deal with surgeon's petulant wife who wants to press charges against her husband's mistress when she learns that she was in his company during the robbery.