Kinji trifft Aria zufällig auf der Straße und folgt ihr in den Besuchsraum des Gefängnisses. Dort findet er Arias Mutter, die zu Unrecht beschuldigt wurde und der viele Jahre Gefängnis drohen. Aria versucht, die Strafe für ihre Mutter zu verringern, indem sie den "Butei Killer" verhaftet. Doch am Tag, nachdem Kinji das herausgefunden hat, fehlt Aria aus irgendeinem Grund in der Schule.
After having nightmares concerning the events surrounding his older brother's death, Kinji ends up following Aria who goes to the police station to talk with her mother, Kanae, who is currently incarcerated as a suspect of the Butei killings. She mentions that Aria needs to find a partner to use her ability, as well as someone known as 'E.U.' The next day, Kinji hears word that Aria will be flying back to London. Later, Kinji goes to meet Riko, who reveals information concerning the Butei Killer, which also mentions his brother who died during a 'sea-jacking', before pulling some moves which sends Kinji into his Hysteria Mode. With his heightened senses, Kinji deduces that Aria's plane is being targeted by the Butei Killer, managing to get on it before it takes off. During the flight, Kinji learns that Aria has a fear of lightning before the Butei Killer announces his hijacking. They soon discover the culprit is Riko herself, who reveals herself to be the great granddaughter of Arsene Lupin, who organised the bike and bus jackings to target Aria, the great granddaughter of Sherlock Holmes, so she can surpass her great grandfather. She also reveals herself to be the one who killed Kinji's brother, who was also her lover. Riko and Aria enter an intense duel, but Riko gains the upper hand by using the true nature of the Quadra, which allows her to manipulate her hair, managing to shoot Aria in a critical area.
Aria vuole scagionare a tutti i costi la madre incastrata dal Butei Killer e per questo in carcere con una condanna a vita. Ma non trovando in Kinji un degno partner decide di tornare il proprio paese, ma il ragazzo capisce che si trova in pericolo, essendo lei l'obiettivo del Butei Killer.
街でたまたまアリアと会ったキンジは、彼女の後について留置場の面会室へと通されることに。
そこには、冤罪によって864年もの懲役を求刑されているアリアの母がいた。
アリアは「武偵殺し」を逮捕して、母の減刑を勝ち取ろうとしていたのだ。
だがキンジがそのことを知った翌日、アリアはなぜか学校を休んでいた。
Kinji sigue Aria que va a la estación de policía para hablar con su madre, que ha sido enmarcado como el asesino de Butei, además de otros delitos, y condenado a 864 años a pesar de los ataques que han ocurrido desde su encarcelamiento. Si Aria es capaz de demostrar que no es el asesino de Butei, la sentencia se reduciría a sólo 742 años.
