Naraku no Shiro - Ichiyanagi Nagomu, 2-dome no junan [The Best Price] Japan

After solving the Amekoushi no Kan case, Ichiyanagi Nagomu receives an invitation from his friend Hiyori to go to the Ruroy castle in Europe. The building is hidden deep within the valley and the only way to enter is through a rope bridge. Nagomu learns of the history of the castle during dinner with the current owner of the castle. The mystery begins.