Arabella Wolf and the Founder's Room (Harry Potter fanfic)

Arabella Wolf never would have guessed that she, of all people, would receive an acceptance letter to Hogwarts School of Witchcraft and Wizardry. Nevertheless, on the first of September she finds herself on platform 9 and 3/4 waiting to board the scarlet red steam train alongside a curious pair of twins, a clever and handsome boy and an effortlessly cool girl with purple hair. As she steps onto the train, it dawns on her that her life will never, ever be the same...