In the Principality of Soville, hidden in the center of alternative Europe in the 1920s, there is calm after World War I. Ordinary people earn a living, the elite seek entertainment, and in the widely known St. Margaret"s Academy scions of noble families are educated. It is into this school that Kazuya Kudzuo, the youngest son of a family of hereditary soldiers from Allied Japan, is transferred. From local students inclined to mysticism and superstitions, the dark‑eyed newcomer immediately receives the nickname "Angel of Death" and the status of an outcast. Trying to dispel melancholy, Kazuya suddenly meets a charming girl with golden hair in a "gothic lolita" costume in the huge tower of the school library. Amazingly, the new acquaintance had been waiting for him long! As it turned out, Viktoria, the illegitimate daughter of a local aristocrat, is effectively imprisoned in the academy like a golden cage. The only entertainment for her sharp mind was visits from her half‑brother Grevil de Bleu, who had gone to the police out of boredom and with the help of a girl known as almost a genius. But with Kazuya"s arrival, circumstances changed. Viktoria tasted freedom and the joy of being able to personally untangle criminal puzzles. Now, against the new great detective and her faithful companion, any tricks of lone wolves and secret societies, no matter what clothes they wear, are powerless.
