The protagonist awakens in a version of Tokyo where "transients" – supernatural beings from fantasy and mythology – live among humans. In this world, both humans and transients utilize mysterious artifacts to fight in duels; duelists organize into guilds, which fight for control of the 23 special wards of Tokyo. The player controls the protagonist as they form a guild of their own, gather companions, and attempt to uncover how they have arrived in this world.

[From Wikipedia]