In Tokyo's downtown district of Ikebukuro, amidst many strange rumors, one urban legend stands out above the rest - the existence of a headless "Black Rider".

Mikado Ryuugamine has always longed for the excitement of the city life, and an invitation from a childhood friend convinces him to move to Tokyo. Witnessing the Black Rider on his first day in the city are mixed up in the commotion breaking out in their city.