Aria follows Kinji to the arcade where he manages to win some plush dolls for her. The next day, Kinji and Aria learn that a schoolbus has been hijacked by the fabled Butei-killer and fitted with a bomb that will explode if it slows down with an armed convertible preventing the passengers from interfering. As the busdriver gets injured when an attempt to stop the convertible is foiled by heat-detection, Aria and Kinji arrive on the scene, taking out the convertible. With the bus slowly running out of gas, Aria finds the bomb on the underside of the bus whilst Kinji finds and destroys the communications sensor. The bomb is disarmed by the sniper ace, Reki, but Aria is injured by another armed vehicle whilst trying to protect Kinji. As she is treated in hospital, she feels disappointed that Kinji didn't meet her expectations.

Kinji works quickly and uses a medicine to save Aria's life. When Aria yells at him as a result, Kinji kisses her to simultaneously calm her down and activate his Hysteria mode. Confronting Riko as she approaches. Just then the plane starts descending, so Aria rushes to the controls whilst Kinji confronts Riko, who escapes after blowing out the plane's door before the plane is hit by missiles, blowing out some of its engines and causing a fuel leak. Despite interference by the government, Kinji manages to ease the plane into an emergency landing thanks to the other Butei. Afterwards, just as Aria is prepared to leave, Kinji agrees to be her partner, though this does not settle well with Shirayuki.