Gosick S01 E01 The Black Reaper will find the Golden Fairy

Kazuya Kujo is an exchange student from Japan. While exploring the library he encounters Victorique de Blois. While talking her extravagant brother Grevil arrives and questions Victorique through Kujo about a locked room murder. Victorique sets her mind to the task and comes up with an improbable but entirely logical answer.