Ash Lynx is a beauty, a genius—and a murderer. Since childhood, he has been under the care of Dino "Papa" Golzine, the mafia boss who molded him into the ruthless killer he is today. Initially, Ash served merely as a pretty face for Golzine's pleasure, but now estranged from him, the 17-year-old Ash leads his own gang with an iron fist. Eiji Okumura is a young Japanese photographer. Traveling to New York as an assistant, Eiji is assigned to work on a report about children living on the streets. There, he meets the teenage gang leader Ash and is mesmerized by the boy—who, in turn, is curious about Eiji's different lifestyle. But this is the dark underground of New York, and recently a series of murders has surfaced in the city, connected only by the words "Banana Fish." With personal stakes in this mysterious battle, it is up to Ash, Eiji, and their allies to discover what exactly "Banana Fish" is, where it came from, and how to get rid of it—before the world as they know it descends into chaos.