The Girl of Four Houses

Charlotte Robinson goes to Hogwarts and befriends the Golden trio before they even get off the train. Making a pact with Harry and Ron that -no matter what house they're sorted into- they will always be friends. If they manage to survive the powers House rivalries, the dangers of Ogres, and the betrayal of st-st-st-stuttering teachers, (Not to mention Lord Voldemort on the back of his head) could Charlotte possibly break free of the hatred and create inter-house unity?