Kotou no OniDemon of the Lonely Island, The Demon of the Isolated Island, The Outstanding Demon, Демон пустынного острова, 孤島の鬼

An adaptation of Edogawa Ranpo's eponymous novel. It's Tokyo and the year is 1924. A young tradesman by the name of Minoura Kinnosuke finds his fiancée murdered inside a locked room. As he struggles to find the culprit, a doctor by the name of Moroto Michio, who has long harboured unrequited feelings towards Minoura, offers to help solve the case.