Detectives Ed Green and Lennie Briscoe from the 27th Precinct report a suspicious cyanide poisoning to the Major Case Squad. When other cyanide deaths occur in a hospital, Goren and Eames initially suspect Colleen Braxton, a nurse who fits the typical criminal profile, but the poisonings continue while Braxton is in custody. The source of the cyanide is tracked down to a batch of laced over-the-counter Necedrol pills. The investigation turns to the victims' families which leads the detectives to a widow named Trudy Pomeranski. The detectives discover she killed her husband and sued the medicine company, then laced other boxes of the same medication around the city in an attempt to cover-up the murder and strengthen her lawsuit. As she used her lawsuit money to buy into a infant clothing franchise, she was caught mailing a cyanide laced letter to the Ledger. She is subsequently arrested while setting up her store, after her franchise agreement was nullified due to a morals clause, when her mother was considered a suspect.

Goren and Eames investigate the disappearance of an adulterous drug-addicted wife of a plastic surgeon. While the doctor says he has attempted to locate his wife, the detectives suspect he is lying, especially when they discover he also has a secret lover but they struggle to find any flaws in the his alibi. Weeks later, body parts of a decomposed woman wash ashore, so the detectives arrange for a false story to be printed in the newspapers, claiming they are from the missing woman. The detectives wait for the husband's reaction when he reads the article, hoping that they can turn his strong ego against him and discover the truth.