Sagisaka Minoru, called Sawada, is a detective in Shinjuku's Intervention Department. Partnered with Narumi Kure, he investigates serial murders displaying supernatural evidence tied to mikura—blood-draining yōkai seeking strength. Sawada stands apart as one of the few investigators who genuinely believes in supernatural causes, unlike his skeptical colleagues. His dedication stems from a personal quest: to prove his daughter Yoshiko was telling the truth. Yoshiko survived a mass murder she blamed on a mikura, only to be committed to a psychiatric hospital. This mission shapes Sawada's relentless focus.

Their investigation leads Sawada and Kure to Hinaru, a survivor of another mikura attack. Hinaru embodies rural migrants seeking a better life in the city, showcasing resilience against the supernatural threat. Sawada's pursuit intensifies as the mikura escalate attacks on hospitals, searching for the injured karas agent, Otoha. These events culminate in a citywide crisis when Eko, a former karas, assaults Tokyo with destructive metal tentacles.

In the climax, Sawada, Kure, Yoshiko, and Hinaru take refuge in an emergency shelter commissioned by the police chief. This sanctuary turns deadly when the chief reveals himself as Ushi-oni, a yōkai preying on the trapped humans. As Ushi-oni attacks Yoshiko, Sawada throws himself in the way, sacrificing his life to shield her. This act allows Yoshiko to escape, fulfilling his driving purpose to protect her. Sawada dies amid the shelter chaos, killed by Ushi-oni's assault.