影片讲述日籍空手道教练收了一个女徒弟,她是他的战友的孙女。她倍受同学欺负,因而要拜宫木为师,学空手道自卫,最后成为空手道比赛的冠军。During a commemoration for Japanese soldiers fighting in the US Army during World War II, Mr. Miyagi meets the widow of his commanding officer. He gets to know her granddaughter Julie, an angry teenager who is still feeling the pain of losing both her parents in an accident and is having problems with her grandmother and her fellow pupils. Mr. Miyagi decides to teach her karate to get her through her pain and issues and back on the right path.