Amid numerous weird stories and warnings of mysterious gangs and hazardous residents in Tokyo's downtown neighborhood of Ikebukuro, one urban legend stands out above the rest—the existence of a headless "Black Rider" who is reported to be spotted racing a jet-black motorbike through the city streets. Mikado Ryuugamine has always desired the excitement of city life, and an offer from a childhood friend persuades him to go to Tokyo. Seeing the Black Rider on his first day in the city, his desires appear to have already been realized. However, when strange happenings begin to occur, everyday folks like himself, as well as Ikebukuro's most colorful residents, become entangled in the uproar erupting in their city.