A Not-So-Golden Couple

For a long time now, Harry Potter and Hermione Granger have played a long game with the magical world. Well now the game is over, but they don't like the result: in that case, it looks like it's time to change the rules! Dark Powerful-Slight Creature-Harmony; VERY OOC Characters; Time Travel; AU GoF onwards; Based on ADVPhoenix's challenge: old idea reposted!