Durarara!! is set in Tokyo’s district of Ikebukuro, where one of our main characters, Mikado Ryuugamine decides to move to at the behest of his childhood friend Masaomi Kida.
They meet up as Mikado gets off the train, and set up walking through the night lit streets of Ikebukuro where Kida explains the ins and outs of living there.
Kida warns Mikado of who to avoid, such as Shizuo Heiwajima, Izaya Orihara, and the mysterious gang known as “The Dollars.”
Shortly afterwards Mikado spots the local legend, the Black Rider: a motorcyclist dressed all in black on a bike that sometimes whinnies like a horse.