Based on a series of urban mystery novels.

Crime-ridden Ikebukuro is a haven for violent gangs, the Yakuza, and home to Makoto Majima. To protect his friends, this charismatic troubleshooter mediates disputes among the warring factions—even fixing problems the police can’t. But when a rising tide of violence results in Makoto losing a loved one, can he ride out the storm, or will he drown in all the spilled blood that floods his streets?

(Source: Funimation)