Ikebukuro is home to many different businesses and gangs. This includes Makoto Majima: the infamous "troubleshooter" who mediates between warring factions. Makoto knows all of the ins and outs of the bustling Tokyo district and strives to maintain peace alongside the G-Boys, who assist Makoto in his troubleshooting endeavors. Led by the charismatic and ruthless Takashi Andou, the G-Boys is the most influential gang in all of Ikebukuro.

However, when the new faction "Red Angels" begins to move in on the G-Boys' turf, immediate tensions rise between them. With numerous enemies scattered around and within the G-Boys, navigating through the streets becomes more difficult for Makoto. While continuing to troubleshoot problems, he slowly unravels a plot that may trigger an all-out war and threaten the entirety of Ikebukuro.