After wrapping up a recording session with his garage band, drummer Roberto (
Michael Brandon) follows and confronts a mysterious stranger who has been stalking him to an abandoned theater where Roberto impulsively stabs him. A grinning puppet-like figure takes photos of the attack from a mezzanine box, which arrive in an envelope at Roberto's home the following day. It appears that he is being blackmailed, but it's not clear from whom or why. Suspects include a club-footed neighbor and various friends. After Roberto confesses to the stabbing, his housekeeper discovers the killer's identity, is murdered, and an increasingly paranoid Roberto sends his wife, Nina (
Mimsy Farmer), out of town. He eventually tracks down the man he stabbed with the help of a flamboyant detective (
Jean-Pierre Marielle) and colorful transient friend Godrey (
Bud Spencer), but both the man and the detective are killed. Roberto's cousin Dalia (
Francine Racette) visits and, against their better judgment, they begin a passionate love affair. Elsewhere, the police use a special camera that can capture the final image a murder victim sees off their eyeball; this technique is used to track down the real killer. ~ Michael Buening