In 1924 in a small, fictional French-speaking European country of Saubure, Kujou Kazuya, the third son of a Japanese Imperial soldier, is a transfer student to St. Marguerite Academy, where urban legends and horror stories are all the rage. There he meets Victorique de Blois, a mysterious yet beautiful and brilliant girl who never comes to class and spends her days reading the entire content of the library or solving mysteries that even detectives cannot solve.