The Karate Kid is an inspirational movie that became a classic due both to the excellent quality of the scrip and the great interpretations of the actors (and all crew involved, of course).
Daniel Larusso comes to sunny California dragged by his mom all the way from New Jersey. He's a skinny, pale and 'not cool' new guy with an attitute (aka 'cry baby'). Daniel's also prone to attract troubles with his impulsive, now and then senseless behaviour and childish sense of humour.
Daniel meets a beautiful girl named Ali Mills, whom his neighbour advises him to stay away from, since she's from 'the Hills'. Not familiar to the expression, he is enlightened to understand she is a wealthy person. However, in all the glory of his 45kg, Larusso decides to stick around and try to win the girl with his charms. Too bad her former boyfriend Johnny Lawrence is # 1 student of the local dojo, and his sensei is not only a Vietnam vet but also a dark master who teaches to have no mercy upon any enemy. Even when you're fighting 5 against 1.
Oddly enough, Laruso expresses the desire to join the fancy Karate Classes, which his mother clearly can't afford. In the meantime, instead of avoiding troubles, Daniel decides to play a prank over his bullies at school, and gives them a shower over the Welcoming Dance while they're not paying particular attention, too busy rolling weed cigars. Has anybody given Daniel a hint of not picking a fight you cannot win? Specially when you know it will be 5 vs 1 and mean guy is really pissed once you're hanging around with his girl? Apparently, not. So just when Daniel is about to be euthanasied by the karate gang, his building janitor, a comic little japanese senior named Mr Miyagi, comes out of the blue in order to defend him. How can a 75 years old defeat 5 teeaner angsted bullies is left for you to understand, though. Mr Miyagi takes Daniel as his pupil and starts his training to defend his honour. Here comes the anthem of the Karate Kid philosophy, a subtle concept hard to catch immediately: "Learn to fight so you don't have to".
I find hard to beleive even a skilled master would be able to teach a skinny guy in one month enough o win the First Place in a Karate Contest, but hey, that's California. Dreamland. Persue your dream and you'll suceed. Nice outfit, also.