Time Immemorial

Hermione loses it after the Battle of Hogwarts. Unfortunately, she still had that time turner and she uses it, sending her back in time, a mystery for the denizens of Hogwarts, circa 1976. OC's are important. Please note, chapters 21-26 could be considered crossovers with JRR Tolkien's Return of the King. In for long haul, y'all.