bad reputation

Y/N brown is bobby browns sister , y/n never stood out like her brother did he was popular , caring , smoked and had done karate whilst y/n on the other hand didn't she was the complete opposite of bobby she was a nerd , someone who didn't stand out , bullied and only had one friend well that was her brother so what happens when y/n leaves encino to go to a boarding school in london for 2 years and returns later to be discovered as the new school's bad girl and changes completely for the better and has a run in with the one and only johnny lawrence ?