Expert New York City police negotiator Ed Zigo (Martin Sheen) joins a team of detectives tasked with finding the notorious serial killer Son of Sam and ending his reign of terror. Zigo's commitment to the task force is not without cost, as it takes him away from his terminally ill wife, Ann (Jennifer Salt). When an unpaid parking ticket leads them to postal worker David Berkowitz (Robert Trebor), Zigo must use his skills as a negotiator to interrogate the suspect and crack the case.