Chen (Bruce Lee), a country boy decides to live with relatives in the city. Fearing for her son's life Chen's mother asks him to take a vow of non violence before he leaves home. He agrees to the request and leaves the country side to live with his family. His oath is abruptly challenged when he learns that his cousins are linked to a local drug scheme and have gone missing. Chen becomes pressured to destroy the "Big Boss" and the villains involved with his families disapearance, a must take action. Lee is faced with a choice... break a pledge to his mother or let his family die?