The story takes place in 1924 at Margaret College, a boarding school for children of nobles in Saint-Val. The transfer student Kazuya Kujo (voiced by Takuya Eguchi) has just arrived at the school and is called the ominous "Black Death" because of his appearance. In fact, Kazuya is an honest and dull boy, but it is precisely this character that makes him always easily involved in strange events that are difficult to explain with common sense. In a murder case, Kazuya met Victoria, a petite and blonde girl (voiced by Aoi Yuuki). This mysterious girl helped Kazuya escape from danger with her superb IQ, and the bond between the two began from then on. In this campus, there are many sensational supernatural events, and behind these events, whether it is ghosts or humans, the answer to this question will be left to Kazuya and Victoria to solve one by one.