Sai Man is a negative person; he thinks that life is hopeless and meaningless. He likes to use a harmonica to play the music that his mother taught him. The music attracts Ah Hua. Classmates of Sai Man make use of their friendship and attempt to rape Ah Hua...世民自幼萬念俱灰，覺得做人很無聊。面對冷酷現實，他不敢面對，只想逃避一切。世民很喜歡獨個兒吹奏母親教他的口琴樂章，琴聲卻吸引著少女阿花。世民的同學們視阿花為援交少女，他們利用世民與阿花的朋友關係，設下圈套，企圖強行蹂躪阿花......
