Franco Arno is a blind man who lives with his young niece and makes a living writing crossword puzzles. One night, while walking on the street, he overhears a weird conversation between two men sitting in a car parked in front of a medical institute where genetic experiments are performed. The same night, someone breaks into the institute and knocks out a guard. Arno decides to investigate with help from reporter Carlo Giordani.

Director: Dario Argento

Writer: Dario Argento, Luigi Cozzi, Dardano Sacchetti

Actors: James Franciscus, Karl Malden, Catherine Spaak

Production: N/A