Your Blood, My Hands

When Wizarding Society is on the brink of destruction, the remaining wizards find an ancient spell to reverse time. But the spell's in an unknown language, and there are more intricacies than they can ever hope to understand. Because although the spell's worked, Harry's stuck on a day that never seems to end. No matter what he tries. Groundhog Day AU, DARK, Tomarry, slash.