While confronting a mysterious stalker in sunglasses, rock drummer Roberto Tobias (Michael Brandon) inadvertently stabs the man when the stalker pulls out a knife. A mysterious masked figure shines a spotlight on the incident and snaps several photographs. Roberto reads about the man's death in the newspaper the next day, and receives a letter identifying the man as one Carlo Marosi. During a recording session with his bandmates, Roberto's maid Amelia catches a glimpse of him with the photographs, but does not intervene.