Pembleton and Bayliss investigate a body found at a burned building, joined by Det. Kellerman from the arson squad.

The arson-murder scenes now include two teenagers, a boy and a girl, one of whom was killed before the fire. Barnfather agrees to another detective for the Homicide Squad IF they solve the arsons, and Giardello can choose his own candidate. Kellerman turns out to be an excellent interrogator and is offered the job.

Since Lewis has unsuccessfully been partnered with every member of the squad, the newbie (Kellerman) is assigned to him. Their first case involves the shooting death of an elderly lady waiting at a bus stop. A young man has captured the shooter stashing his gun, but he has trouble getting the cops to watch the tape. Howard has made sergeant and is trying to establish her authority in the squad, but irritates her colleagues. The climax is an arrest of the groom during a wedding ceremony.

Pembleton and Bayliss work with FBI agent Steven Van Brandt to stop a killer working his way up I-95 from Florida toward Baltimore.

Pembleton and Bayliss investigate the murder of a man outside a gay night club.

Pembleton and Bayliss look for a gunman who opened fire at a crowded shopping mall, critically wounding a 10 year old boy.

John Munch and Kay Howard try to frighten a drug dealer into confessing to murder, by using his love of Edgar Allan Poe's works to their advantage. Meanwhile Munch's date with a beautiful colleague backfires when he meets her roommate.

The detectives pursue a sniper who leaves games of Hangman at every crime scene.

Another sniper strikes Baltimore as soon as the first is apprehended.

Lewis and Kellerman take a road trip to extradite a Baltimore murder suspect from Pennsylvania. It should be an easy assignment, but Meldrick and Mikey make things hard on themselves by losing the suspect on the way back.

During the investigation of a burglar found dead with no apparent injuries, the detectives find that he visited an ER for a gunshot wound and may have received bad surgery.

In the second part of a story started on Charm City (1996), Bayliss and Pembleton work with Lennie Briscoe and Rey Curtis to find the people involved in the NYC subway bombing and the Baltimore church bombing five years earlier.

A murdered ex-cop's son decides to conduct his own investigation when Munch and Russert find themselves stumped in their search for the killer.

The man who was acquitted of murdering a cop's father is found dead.

A male prostitute offers to reveal the identity of a multiple murderer as part of a plea bargain. He admits to luring in the victims and stealing their rings, but not to being the killer. The Homicide Squad takes turns on a stakeout next door to the suspect. Interactions between squad members and between the couple whose house they "occupy" run the gamut of emotions.

The murder of a young girl revives memories, especially in Bayliss, of an earlier case--Adena Watson, which was not resolved. Pembleton is the primary and is angered by Bayliss' interference and obsession with the old case. A reported sexual assault on a friend of the murdered girl produces a connection but no proof. Will this be another case which has no definitive answer?

The desk clerk at the New Moon Motel hears shots and calls 911. Lewis and Kellerman find the body of an ex-con wearing only one boot. The victim's classic motorcycle is missing, as is his handgun. As they interview motel residents, they find a family of illegal immigrants, a prostitute who swims in the nude, homemade drugs, wads of cash, illegal guns and uncover an unreported self-defense shooting. But what about the killer of Charlie Wells?

Two young black men are found shot to death at a project where Black Muslims have a security contract from HUD. Residents are hostile to the police initially. When one bereaved mother tells Russert that she had called 911 and half an hour passed before help arrived, they find there was a beat cop just a few blocks away. He admits he waited because he was in fear of his safety. Internal Affairs gets involved when the autopsy shows one of the boys bled to death over a period of about 20 minutes. Lewis and Kellerman are alienated over the racial issues.

The body of a 71-year-old world class swimmer is found in a pool where the ME says he was for 24 to 36 hours. A man claiming to be his biological son asks the detectives to test the corpse's blood for a DNA match. The ME discovers cancer in the corpse and massive amounts of steroids. Then a woman from the NSA demands Bayliss and Pembleton help her find her "friend," the purported son. The detectives are flabbergasted when someone comes in and confesses to speeding up the cancer effects with the steroids!!

A drug war is being fought--shipments hijacked, smalltime dealers shot, and even a family in their home are killed, leaving a small daughter hiding in a closet. Kellerman and Lewis catch the case(s) and learn a lot about the strange code of honor involved. The Narcotics detectives bring in a self-confessed killer with the murder weapon, but that's not the "whole truth."

Lewis announces to Kellerman that today is his wedding day and promptly vomits. Because Lewis involves all the squad in the preparations, Giardello and Howard catch the murder of a radio talk show host, which ends with Gee's firing/killing the suspect. Munch is sure the wedding is an elaborate practical joke, but the others work frantically to get flowers, food, etc. for the nuptials. Pembleton's wife makes this day very memorable.

Three people are shot during a robbery at a burger place; two die, a teenage girl and a male customer. Pembleton and Bayliss investigate. They discover the other victim (shot in the knee) was the shooter's friend, and during his interrogation Pembleton has a seizure and is taken to neurosurgery. Meanwhile Lewis and Kellerman investigate "The Bowling Ball Murder"-someone dropped the ball from an overpass.