Immortal Landslide

Mina Smith seems like any other Hogwarts student except that she has attended Hogwarts many times over the decades. Cursed to live forever Mina tries to keep to herself but that all changes when she meets Sirius Black. A year after Sirius's death she finds herself back at Hogwarts trying to keep herself out of the clutches of the Dark Lord who wants to take her Immortality.