Diadem

It's funny how important timing can be. Take the case of Rowena Ravenclaw's Diadem, for instance. Decades after being destroyed to rid the world of Voldemort, the Diadem is found to be much more significant than previously thought. With war looming on the horizon, an infamous but youthful Harry Potter is sent on a desperate dimension-hopping gambit to replace it with a new one.