Frank McGarrity, a young lawyer in Princeton, takes the case of William, who won't give his last name but carries plenty of cash. William confides he murdered a man but assures him he won't kill again. He doesn't admit that he longs to be the most famous serial killer ever and plans to execute thirteen privileged people who took advantage of his indigent mother or him. McGarrity is torn between legal ethics and moral right. As a lawyer, he must keep any secrets as long as a client doesn't reveal an intent to commit a future crime. After visiting Biscuit Buckingham, a jailed bank robber client who was caught because he stopped to help a dog, McGarrity finds out his legal mentor, Jack McCabe, has been killed by an arrow in the back. He shadows William and realizes he's scoping out his next victim, reporter Cindy Halsey. Back home he discovers his fiancee Trish is having an affair with a doctor. He moves out of their apartment into Jack's vacant one. Biscuit escapes from jail in William's laundry truck. William murders a nun and Doctor Benjamin, Trish's lover. McGarrity concludes he's the only one who can stop the "bow sniper." William coerces Biscuit into robbing another bank and abandons him after the job. While Biscuit manages to elude the police in huge Mercer County Park, William executes his grade school teacher. Biscuit meets with McGarrity in a Trenton cemetery. After Biscuit tells him where William lives, he convinces Biscuit to plead guilty to bank robbery and cooperate against William. That will force the court to relieve him as William's counsel due to a conflict of interest on the bank robbery charge. McGarrity drives to William's hideout and finds a scrapbook of victims. He goes to the home of Elaine, the next target. Although with her two children she's about to separate from her husband, McGarrity persuades her to tell the authorities about her ex-boyfriend-Ernest McGinty, who is using the alias William. William finds out from a