Lewis and Crosetti uncover a woman who's been killing her husbands for insurance money. Howard tries to keep her cases-solved record perfect, but she is reassigned with Felton as her partner. Bolander convinces Munch to help him finish up an unsolved case. A new guy, Tim Bayliss, from the mayor's office gets his first case in homicide, the murder of an 11-year-old girl. His partner Pembleton, we find out, is less than enthusiastic to work with him or anyone else in the unit.

Bayliss and Pembleton continue to struggle with the Watson case. Bolander and Munch discuss ""iguana style"" and are called to check out the homicide of a victim that isn't dead, at least the first time they're called. While checking out some leads for the Watson case, Crosetti gives his theory on the conspiracy to kill Abraham Lincoln. Lewis wants to flood Memorial Stadium. Bolander expresses an interest in Dr. Blythe; Munch advises and sends flower's in Stan's name. Danvers needs a stronger case; however, Howard is frustrated with a dead end. Then the ghost of the victim leads her to the undiscovered proof. Tim attends Adena's funeral.

Crosetti and Lewis investigate the shooting of a fellow police officer whom Crosetti regards as a son, Howard suspects a rabid Spiro Agnew fan of murder but ends up solving the Calpurnia Church case meanwhile Bolander makes a friend whose death interrupts his date with Dr. Blythe.

Crosetti focuses his investigation into the shooting of Officer Thormann on one suspect, while Lewis continues to investigate. Meanwhile, Pembleton and Bayliss pursue different leads in the murder case of eleven-year-old Adena Watson.

Pembleton and Bayliss have only twelve hours to grill their prime suspect in the Adena Watson case before they must let him go.

While Giardello is busy sending off an old friend to retirement Pembleton and Bayliss investigate the murder of a dog, Howard and Felton argue over whether Felton finds Howard attractive while dealing with a drug-related homicide and Bolander and Munch take Dr. Blythe's son on a ride along. Meanwhile, Crosetti takes care of the bed-ridden and blind Thormann.

Howard and Felton are in court over the Pony Johnson case, Crosetti and Lewis go head to head with the Secret Service and Bolander and Munch argue over drug legalization. Meanwhile, Pembleton gets an unexpected job offer.

Quitting smoking dominates the conversation ad behavior of the homicide detectives even as they solve what may be a gang-related killing of a 14-year-old boy. Lt. Giardello discovers a secret asbestos removal project on the third floor and confronts his superiors on behalf of his squad.

The homicide team pulls the graveyard shift on the hottest night of the year. Bayliss is consumed by the Adena Watson case, driving a bigger wedge between him and partner Pembleton. Giardello finds a baby in a cage. A renegade Santa Claus runs loose in the building and the whole squad tries to figure out who's responsible for a candle that keeps getting lit.

All the detectives scramble to solve the case, when the mother, in a family on vacation, is murdered during a holdup. The husband has a hard time dealing with the reality of him not doing anything during the situation and Felton's indifference. When the suspects are found Howard is convinced that the youth who confesses to the murder didn't do it.

Gee informs the detectives that they must meet with a sensitivity consultant. Felton protects a friend who's going to help his terminally ill father commit suicide. Pembleton investigates a routine murder that escalates into a case of possible police brutality. Bolander has no intention of meeting with the consultant to the point where he takes a suspension without pay. Lewis investigates the death of the father of Felton's friend and discovers the truth and confronts Beau.

Things begin to heat up between Pembleton and Gee over the alleged police brutality case and one of the suspects is an ex-lover of Kay's. Bolander meets a waitress who encourages him to resume his cello playing. Munch's girlfriend is less than enthusiastic when he surprises her with a new fish for her tank. Frank, in the box, gets the confession that Gee is looking for. Unfortunately, the suspect is anything but guilty of that crime.

Bolander asks Kay if she would double date with him and Linda, to try to take the pressure off his first real date. A slain phone-sex operator is found clutching a note naming her boss as the perpetrator, Bayliss and Pembleton investigate. Munch has trouble dealing with Bolander's happiness, so he crashes the double date and makes everyone miserable. A man is shot to death over a pen at the library, Lewis and Crosetti investigate and find a man with a pen fetish. As Bayliss looks into the murder he begins to get involved.