Ash Lynx, a 17-year-old boy, is the boss of a street-kids gang in New York.
One day, a man who was murdered before his eyes entrusts him with something.
And the last words uttered by that dying man was the phrase, ""BANANA FISH"". That is the word his brother, Griffin, often mutters. Ash has a destined encounter with Eiji, a kind Japanese boy who comes to New York as a cameraman assistant.