After Ryusaku Nishikawa and his girlfriend Katsuko are attacked by a gang, he trains in karate to seek revenge. Years later, Ryusaku is a skilled martial artist preparing for an inter-school match, but his past resurfaces when Katsuko, now involved with the gang, brings tragedy. In a final confrontation, Ryusaku faces the gang and finds redemption through his karate, with the support of his friends.