Ralph Macchio stars as Daniel LaRusso, a teenager who moves with his mother Lucille (Randee Heller) from Newark to California. His mother has a wonderful new job to go to, but Daniel finds it harder to fit in with the Californian kids at his new school. Daniel ends up being the victim of bullying, and although he does manage to talk his way out of a number of fights he is eventually cornered by members of an aggressive karate club who beat him soundly. These are the Cobras, who have taken a dislike to Daniel because he has struck up a relationship with Ali Mills (Elisabeth Shue), the Cobra leader's ex-girlfriend. As he is passing out from the beating, he sees the old Japanese handyman Kesuke Miyagi (Pat Morita) coming to the rescue and beating the karate students at their own game.
Together Daniel and Mr Miyagi find that the Cobras' attitudes to fighting are coming from what they are being taught at their karate club by their aggressive teacher John Kreese (Martin Kove). Miyagi agrees to teach Daniel his karate style, so that he can fight at an upcoming karate competition, but much of what Miyagi has to teach is so unconventional Daniel wonders if he will ever learn enough to win. Daniel will have to learn that fighting isn't always the answer to a problem, and will need to find the self-confidence and faith in himself to deal with the problems he faces.
This fine coming-of-age drama set the standard for the genre when it was made, and still holds up well. The basic story is sound and the plot moves along well, but it is the characters which particularly appeal, especially Daniel and Miyagi. Ralph Macchio does a fine job as the put-upon lad who has much to learn about himself, and the evergreen Pat Morita is outstanding as the humorous but intelligent old Japanese handyman. The message of the film is clear, that the development of maturity and self-confident is more important than the learning of fighting skills, but the message is not so heavy-handed that it put kids off. Instead, the film provides an inspirational story that motivates the audience to find the same qualities in themselves.