A police detective named Yosuke Kobayashi suffers a mental collapse after a serial killer murders his wife. The trauma fractures his psyche, giving rise to two new dominant personalities: Kazuhiko Amamiya, a calm and brilliant criminologist, and Shinji Nishizono, a reckless and violent psychopath. After Kobayashi, under the control of one of these identities, hunts down and kills his wife's murderer, he is imprisoned. Upon his release, the personality known as Kazuhiko Amamiya is now in control. He is taken in by Machi Isono, a sharp and resourceful female criminologist who runs a private detective agency. Working alongside her, Amamiya is drawn into a series of new, even more disturbing serial murders. The victims and killers in these new cases share a strange, unifying mark: a barcode tattooed in their left eye, a mark that Amamiya himself possesses. This clue leads him to believe his own identity is a lie and that his alternate personalities have existed since childhood, long before the trauma that seemingly created them.

The investigation reveals a sprawling and sinister conspiracy orchestrated by a powerful and secretive organization known as the Gakuso Corporation. Gakuso possesses advanced genetic technology and is attempting to recreate the ultimate serial killer, a legendary deceased American rock star and terrorist named Lucy Monostone. The organization has engineered the barcode program, using it to implant and cultivate artificial personalities in human hosts. Amamiya and Nishizono are revealed to be two such programmed personalities, designed to eventually merge and form the core of a new Lucy Monostone. The narrative follows Amamiya and Machi as they delve deeper into this conspiracy, encountering a gallery of grotesque killers, all pawns in Gakuso's larger game. Their investigation brings them into conflict with other hosts carrying fragments of the Lucy personality, including a young teenage boy named Tetora Nishizono, who is dominated by another version of the Shinji Nishizono personality. The story also reveals that Machi's own younger sister, Miwa, is a new-generation barcode host carrying a crucial personality fragment needed for the resurrection of Lucy Monostone.

The live-action television miniseries, directed by Takashi Miike, unfolds across six episodes, each structured around a different gruesome case that ties back to the central conspiracy. The first episode, Memories of Sin/Drifting Petals, introduces Amamiya and the bizarre case of a killer turning victims into human planters. The investigation into a serial killer who removes fetuses from pregnant women follows in How to Create a World. The third episode, Life Is a Constant Double Helix, sees Amamiya go undercover at a militaristic high school to investigate a mass suicide of forty girls, all of whom are part of a new generation of barcode users. The fourth episode, The Crushed Ant, involves a grisly discovery of dismembered body parts and a turf war between rival gangs. In Coronation of the Cursed King, members of the barcode cult begin spontaneously combusting, leading the team to a hospital with a secret floor where horrific experiments take place. The final episode, Soaring Souls and Human Bondage, concludes the series as the police attempt a mass cover-up, forcing Amamiya and his remaining allies to pursue the truth on their own. The story culminates in a confrontation with the forces behind the barcode conspiracy as Amamiya fights to reclaim his missing son and understand his own fragmented identity.