Ryo Saeba is the leading City Hunter in town, tackling cases alongside his partner Kaori. A model called Ai Shindo has been assaulted and hires him as her bodyguard. Shinji Mikuni, the chief of an IT firm that contracted Ai for a promo, turns out to be Kaori"s old acquaintance, pulling them into the plot. At the same time, mercenaries converge in Shinjuku while a heavyweight arms dealer lands in Japan with a fresh weapon. With Mikuni involved, Ryo and Kaori begin drifting apart and their partnership is tested.