Kaoru Kanou, a corporate president who is under suspicion for arrest, holds a ballroom event. Among the invitees are Shinjūrō Yūki, a curious detective, his strange assistant, Inga, and Rie, the daughter of police detective Rinkako Kaishō. During the event, Kanou is mysteriously murdered by a knife in his back, with suspicions placed on a member of the SP police who was found shot dead in the hallway. However, thanks to Shinjūrō's detective work, along with the strange abilities of Inga, who transforms into an adult capable a forcing an answer to any one question she asks someone, they soon discover the culprit is Kanou's wife, who wanted him to die a hero.

Rie calls on Shinjūrō and Inga to accept a request from Mitsuko Sasa, whose adopted brother Kazamori caught on fire and died, allegedly related to a curse from her father, Komamori, who died in a similar manner seven years ago. As Izumi's group conducts their own investigations on the cause of Kazamori's death, Inga uses her powers to reveal that Kazamori is actually a supercomputer.

As Rinroku is interviewed via a live video feed, Shinjuurou has Rie tell everyone about the Rinroku that appeared in her home at the time of the explosion. To Shinjuurou's surprise, Inga is called in as a witness to question Izumi, forcing her to reveal secrets about Rinroku's involvement in illegal software used prior to the war. As the hospitalized Rinroku is discharged, he is killed in a car explosion. After speaking with Rie, Shinjuurou suspects something is amiss and manages to learn more about Bettenou from the novelist, further founding his theory that Rinroku used Bettenou's power to fake his death.

Shinjuurou, along with Rie, Izumi and some others, receive strange invitations supposedly sent by Rinroku. They are brought together at a table where they are presented with weapons, Shinjuurou believes that the imposter Rinroku was the one who appeared at Rie's home, deducing that the Diet member and Rinroku's bodyguard caused the explosion. It is at this point that Rinroku himself seemingly appears with Inga, only for Shinjuurou to deduce that he is actually Izumi's assistant, Shingen Hayami, using Bettenou's power, with the real Rinroku having disguised himself amongst the attendees, having previously faked his death. After a fierce battle, Inga defeats Bettenou and devours her. After the incident, Shinjuurou explains his relationship with Inga to Rie.