Not This Time, Mister Potter

Due to a rebellious Grim Reaper Voldemort did not die at the battle of Hogwarts. Now 8 years later Harry and Moldy Shorts are battling once again and when Voldemort's new spell helps him gain the upper hand in sending Harry to the afterlife, Harry is given a chance to go back in time to change things. Time travel. Canon pairings though little if any fluff.