Ep. 4: Narihisago returns to investigate the Gravedigger copycat killer while Haruka Kazuta appears.
After the Pyrotechnician’s suicide, Narihisago remains in solitary confinement, causing tension among the investigation team. Unable to find a replacement detective, they are forced to collaborate with him again to hunt the Gravedigger, a serial killer who buries victims alive and livestreams their deaths. Sakaido identifies a depressed local man as the perpetrator, but Kazuo determines he is merely a copycat, leaving the original killer at large. Police arrest the copycat but fail to save the victim in time. Meanwhile, Momoki discusses Narihisago’s killing urges in prison, affirming their friendship. The episode concludes with Haruka Kazuta, a missing man previously targeted by the Perforator killer, suddenly kissing Hondomachi at the copycat’s crime scene.
Episodes
- Ep. 1 · Sakaido wakes in the Perforator's well after Hondomachi is kidnapped by the serial killer.
- Ep. 2 · Sakaido encounters John Walker while Hondomachi orchestrates her own rescue from the Perforator.
- Ep. 3 · The Pyrotechnician serial killer uses fireworks to snipe bystanders before being arrested.
- Ep. 4 · Narihisago returns to investigate the Gravedigger copycat killer while Haruka Kazuta appears.
- Ep. 5 · Kazuta's identity as Gravedigger is exposed, leading to a fatal explosion and the reveal of Inami as the mastermind.
- Ep. 6 · Kazuta's Death and the Investigation into John Walker's Identity
- Ep. 7 · Hondomachi investigates Narihisago and Kiki Asukai while Momoki is framed for John Walker
- Ep. 8 · Togo leads a rescue mission to extract Hondomachi from Kiki Asukai's id well while Momoki faces police interrogation.