A nearsighted burglar breaks into a woman's apartment and awakens her when he stumbles over some boxes lying on the floor. Scared, the burglar takes his leave. Later, he learns of a local scientist who has invented a serum that cures nearsightedness. He breaks into the laboratory and shoots two scientists. He injects himself with the serum, only to discover that it was designed to cure the eyesight of bats. The man begins slowly changing into a man/bat hybrid.