What if Minerva McGonagall had ascended into the role of Headmistress after the death of Albus Dumbledore?

What if the school had never been overtaken by Death Eaters and the Ministry?

What if the trio had been forced to return to Hogwarts for their final year of schooling?

What if Draco had learned the error of his ways and taken refugee at Hogwarts?

What if Viktor and Hermione grew closer together, while Harry and Ginny drifted further apart?

That's up to you.