Snakes

It had been nearly four years since Harry left Hogwarts in his seventh year to hunt for Voldemort's Horcruxes and just over three years since he decided he had enough of being used as a pawn in some old fool's chess game, even after the old coot was dead. Harry is neutral in the war until he decides to help a certain blonde Slytherin and in turn Voldemort himself what happens next?