A woman is apparently murdered in a New York auditorium under very suspicious circumstances one evening during a performance. Helen Hardwick happened to be in attendance that evening, as she had written the play that was being performed, and she was the only person to have caught a glimpse of something peculiar just before the murder. She also heard an ominous laughter which would continue to haunt her. Was it coincidence that the 'retired' Gray Phantom arrived in the city immediately after the murder...