The Detective Is Already Dead

Kimizuka Kimihiko has a knack for attracting trouble, often finding himself in the middle of a crime scene or witnessing illicit activities by chance. This pattern repeats when his flight experiences an emergency, prompting the need for a detective aboard. Siesta, a self-proclaimed detective with silver hair, intervenes and forces Kimizuka into her investigation as her assistant. Their involvement in various high-stakes cases takes them around the world, resolving crimes and saving lives.

Three years later, Siesta's death marks the end of their adventures. Kimizuka then decides to lead a more ordinary high school life, keeping a low profile for a year. However, his peaceful existence is disrupted when a girl resembling Siesta appears, drawing him back into a potentially complicated situation.