A half a year after the the war of the Yellow Scarves, Ikebukuro has begun to return to normal. High school is in session, Izaya is back to scheming, and Celty, the legendary headless rider, is still chased by the police as she rides through the town. But a few unusual things have slipped into the mix. Gradually, thanks to outside elements, Ikebukuro will be thrown back into chaos.