A street in New York. The doorbell rings in a telephone booth. A man picks up the phone. The Deadly Nightmare begins. PR agent Stu Shepard basks in the role of the dynamic, successful doer. To hide his secret dates with actress Pamela from his wife, he has a special trick: He calls Pamela from a phone booth at the same time every day. When Stu is about to leave the phone booth again, the doorbell rings. Instinctively, he picks up the phone and falls into a hellish trap. The unknown caller is a sniper and serial killer who has pointed his sniper rifle at Stu. His message is: If you hang up the phone, you're a dead man.