East Mikado is a fantasy land reminiscent of the feudal Japan. The protagonist of the game is a young samurai entrusted with the task of tracking down a mysterious being known as the Black Samurai. It appears that lately more and more people were being turned into demons because of the books handed to them by that enigmatic person. As the hero and his friends investigate the matter they become involved in a conflict between two faiths, the Mikado church and the cult of Gaia.