A psychotic killer, Garland “Red” Lynch, uses a campaign of terror to force San Francisco bank teller Kelly Sherwood to steal $100,000 from the bank for him. Despite his threat to kill her or her teenaged sister Toby if she goes to the police, Sherwood contacts the San Francisco office of the FBI, where agent John Ripley takes charge of the case.
Ripley interviews a woman who implies that she’s involved in some way in a serious crime, but before she can give Ripley the details, Lynch murders her. Sherwood continues to be terrorized with phone calls, an asthmatic condition making the unseen Lynch’s voice all the more sinister.
The FBI identifies the criminal, noting that Red Lynch has a record of convictions for statutory rape, forgery, criminal assault, armed robbery and murder. They track down his girlfriend, Lisa Soong, whose 6-year-old son has just had a hip replaced. Lynch is paying all the hospital bills. Because of this, Lisa refuses to believe that Lynch is a criminal and will not cooperate with the investigation. Ripley nevertheless manages to get some information about “Uncle Red” from the boy.
Lynch finally gives Sherwood a time and date to steal the money, and just to make sure that she does, he kidnaps her sister Toby and holds her captive. The climax is a chase through Candlestick Park after a nighttime baseball game between the San Francisco Giants and Los Angeles Dodgers. Ripley and his men ultimately surround Lynch on the infield of the stadium.