The story revolves around a mathematician, Tetsuya Ishigami, who becomes embroiled in a murder investigation. Ishigami, a quiet and unassuming man, is a genius mathematician who has a secret life. When a woman is found dead, and her husband becomes the prime suspect, Ishigami becomes obsessed with the case. As the investigation unfolds, Ishigami's own life begins to unravel, revealing a complex web of secrets and lies.