Briscoe and Green investigate the shooting of a best-selling mystery writer and the death of her accountant, with a love triangle as a possible motive for the crime.

The death of a parolee, who was a hit man, leads to a wealthy widow and daughter and whether they hired him to kill their rich relative.

When the witness in a jewelry store robbery-homicide fails to appear in court, McCoy suspects foul play until he discovers that the man is a fugitive in a 20-year-old murder case.

While investigating the death of a teenaged girl, the detectives stumble on a pattern of crimes that indicate they are after a serial killer. The suspect, however, puts the prosecutors through an ethical ringer when he discloses his attorney's knowledge of the victims and their whereabouts.

When a Holocaust survivor is murdered on the eve of her testimony in the deportation trial of a former concentration camp guard, McCoy prosecutes the man and the Neo-Nazi sympathizer who's running a fundraising web site for him, and must debunk a Holocaust denial defense which claims that the millions of deaths resulted from disease, pestilence and wartime conditions.

Fontana and Green are baffled by a series of flu-related deaths until they discover that the victims were given fake vaccine. McCoy goes after the con man who distributed the vaccine for murder.

Police turn their attention to the murder of an undercover reporter, but realise that the killer isn't as guilty as he appears.

After the body of a teenage boy is found dead in a warehouse, detectives use DNA to connect the boy to a convicted rapist and serial killer, then to the boy's mother, Allison Ashburn, the convict's ex-wife. While trying to solve Danny's murder, Fontana and Green learn that he recently got his girlfriend Tina pregnant, and his mother had seen him recently when she had given him money despite having claimed she hadn't seen him for months. Allison finally admits that she murdered her son after the police arrest her new husband John, but claims she did it to save the world from her son, whom she was convinced would become a monster just like her father. Borgia and McCoy face an uphill battle trying to convict the perfect soccer mom.