Ryo Saeba, renowned as the "City Hunter," teams up with his colleague Kaori to solve cases. Their latest client, Ai Shindo, hires them as her security after being attacked. Romance unexpectedly blooms between Kaori and Shinji Mikuni, the CEO of the company Ai works for. However, their love affair is further complicated by the presence of mercenaries in Shinjuku and a new arms dealer in Japan. As Mikuni becomes more involved, Ryo and Kaori's relationship becomes strained.