Olfactogram.

Amateur band guitarist Minoru Katagiri becomes unconscious when someone hits his head at her sister's house. When he regains consciousness a month later, he learns that her sister was killed as a victim of a series of bizarre murders that day. In addition, his sense of smell developed abnormally due to the after-effects of being beaten, and he acquired a special ability to visualize odors. Minoru pursues the criminal by making full use of this special ability.