Sound engineer Jack Terry (John Travolta) has "wired" Sally (Nancy Allen) when she is meeting the reporter, to whom she will be presenting the evidence that the governor was killed due to a shot in his car tire, which resulted in the so-called "accident" witnessed and recorded by Jack.
However, when Jack listens to their conversation from nearby, he notices that she isn't meeting the reporter, but a different man. It is Burke (John Lithgow), who did the shot in the car tire, and later switched the tire. Burke has already killed two Sally-lookalike girls to make it appear that a serial killer is busy.
Jack doesn't arrive in time to prevent Sally from being killed by Burke, but kills him with his own weapon. He uses Sally's dying scream (which he recorded) for the shower scene in the cheap movie that he was working on at the beginning of the film. The crew is happy with the realistic scream.