Romeo, A.K.A. Kosuke Matsuyama (Shun Shioya), is a second-year high school student. A nice, normal, nonviolent type, he suddenly finds himself in the middle of a rampaging crowd of Korean boys, outraged by insults perpetrated by several of his idiotic class-mates on two Korean girls. He makes a narrow escape, but soon after, he and his best bud Yoshio (Keisuke Koide) are sent by their home-room teacher to invite the Korean students to a friendly soccer game as a way of restoring the peace.
Trembling like black-uniformed leaves, they enter enemy territory, where Kosuke encounters a doll-faced, but serious-looking girl (Erika Sawajiri) playing a Korean folk song, “Imjin River,” on a flute. He and Yoshio are also nearly lynched by her older brother Lee Ang Son (Sosuke Takaoka) and his gang, but he is already smitten — and eager to learn that haunting tune.
The story concentrates on Kosuke’s struggle to not only master a song, but win the love of a girl who seems to live in an alien, hostile world. Meanwhile, Ang Son and his crew are street-fighting with Japanese toughs as if playing a contact sport, with one side scoring hits, then the other. He is macho to a fault, but when he learns that his sweet-heart (Kyoko Yanagihara) is pregnant and determined to keep the baby, he faces a choice that makes him quail: grow up or cop out.