Mikado Ryuugamine is a young boy who craves the abnormal and supernatural, but his quiet life in the countryside offers no opportunity for adventure. With some encouragement from a childhood friend, Mikado moves to Ikebukuro, a lively downtown district in Tokyo. However, the naïve boy may be in for a lot more than he bargained for.

Ikebukuro is home to a host of strange individuals, such as a monster of a man dressed in a bartender's outfit, a sadist who sells information for fun, and an underground doctor with an odd infatuation. But the most unusual of them all is the legendary "Black Rider," a headless being who silently rides through the night on a pitch-black motorcycle. When Mikado witnesses this urban legend on his first night in the city, his initial excitement triggers a thrilling but deadly sequence of events, affecting numerous others throughout the city.