Ms. Tsuzuri takes her students to a hot spring to undergo Butei training, which is supposed to begin the next day, however strange things start happening as they make their way to the rooms in which they are staying.
Riko gets her rosary back, but things get hairy when Vlad of Innumerable Sins bursts onto the scene. With only one bullet left in each of their guns, the trio decide to rely on Kinji's hunch to bring the beast down.
Kinji and Aria arrive at the mansion disguised as a stealthy butler and charming maid. When a familiar face answers the door, the duo and their ring leader must think on their feet in order to retrieve Reki's rosary.
Aria finds herself disguised as a maid after reluctantly agreeing to help Riko with her plan to infiltrate Vlad's mansion. Later, Kinji learns about Riko's past from Jeanne D'Arc, who suggests that Vlad is a demon.
Kinji's nerves are shot over the all-out war between Shirayuki and her pint-size protector, so he takes the job into his own hands. But after a night of fireworks, the shrine maiden gives him the slip.
Aboard a quickly descending jetliner, Kinji corners the Butei Killer, who invites the high-schooler to join a secret organization, and then makes an explosive escape. As Kinji and Aria try to land the plane safely, they get some unexpected help and interference.
Kinji follows Aria through town to the police station, where he learns why she's so desperate for a partner. After discovering that she's flying back to London, Kinji realizes she could be the Butei Killer's next target.
Second-year student Kinju is racing death trying to keep a bomb on his bike from blowing, when to the rescue comes a hot-headed girl with major combat skills, who unwittingly fingers the trigger on Kinju's secret "hysteria mode."