Cardia (voiced by Saori Hayami) looks like an ordinary girl, but in fact, she has a poison that can corrode everything she touches. She lives in loneliness all day and is arrested by the military. By chance, Cardia meets a thief named Robin (voiced by Tomoaki Maeno). He is cheerful, optimistic and overconfident, and is not afraid of the poison on Cardia. The two travel together to London, where the mystery of Cardia's life lies. Along the way, Cardia and Robin meet all kinds of companions. Vampire hunter Van Helsing (voiced by Junichi Suwabe), Frankenstein (voiced by Tetsuya Kakihara), who is calm and kind with super intelligence, and Barbicane (voiced by Shotaro Morikubo), who is a little frivolous but has a super high IQ.