Stu Sheperd (Farrell) is a slick publicist trapped in a New York City phone booth after he picks up the ringing receiver and is told that he will be killed if he hangs up. The man on the line, a serial killer with a sniper rifle, proves that he's not kidding when the small red dot from the infrared rifle sight appears on Stu's chest. The sniper/caller sets up the scene to make Stu appear to be a crazy man with a gun who refuses to leave the phone booth. When the police, press, Stu's wife and his wanna-be mistress arrive at the scene, Stu must try to warn and protect the innocent from the sniper while preventing the sniper or police from killing him. Set in real time, it's going to be a busy afternoon.