New York, 1985. Ash Lynx, a seventeen-year-old gang leader raised by the ruthless mafia boss Dino Golzine, stumbles onto a mysterious substance called "Banana Fish" — the same words his older brother muttered after returning broken from war. As Ash digs deeper, he crosses paths with Eiji Okumura, a gentle Japanese photographer's assistant whose unguarded kindness becomes the one thing the streets haven't taken from him. Pursued by the mob, the FBI, and the ghosts of his own past, Ash fights to expose the truth and protect Eiji from a world that wants them both dead.