Renowned for his volatile temper, Shizuo Heiwajima sends an entire biker gang from Saitama to the hospital. Their leader, the strong and handsome womanizer Chikage Rokujou, arrives in Ikebukuro to settle the score. However, Shizuo is not his only target; he and his gang also intend to take revenge on the Dollars, who have apparently been wreaking havoc in Saitama. While Masaomi Kida is away, Mikado Ryuugamine encounters an unusual problem. His new junior, Aoba Kuronuma, effortlessly discovers the identity of the Dollars' leader and insists on befriending Mikado. Although Mikado tries to distance himself from the Dollars following the advice of an anonymous user—who he assumes is Kida—their online chat's newest member shares unsettling stories of the gang's violence, making it difficult to ignore. Meanwhile, Celty Sturluson goes on a job for yakuza member Haruya Shiki. In her absence, Shizuo is attacked by a young girl who refuses to explain the reason behind it. As Shinra Kishitani tries to help, a mysterious Russian pair shows up with but one goal: to kidnap the strange girl.