Two Steps Back
Disclaimer: I don't own Harry Potter. All recognisable characters, content, or locations belong to their respective owners. No copyright infringement intended.
Author's Note: The obligatory time travel fix-it fic.
Prologue:
It starts as a trickle, inconsequential rumours Harry Potter brushes off with the over-confidence of a job well done, and the certainty that Albus Dumbledore is always right.
That trickle becomes a downpour, and Harry's over-confidence burns away with the heat of a thousand suns with the first - though not last - attack on Diagon Alley.
Harry is 21 at the time, a trainee unspeakable, and Voldemort is as hideous as he has ever been. He has behind him a small army of Death Eaters, disgruntled werewolves, vampires, trolls, a pair of giants, and a small horde of dementors.
Overkill?
Absolutely.
Moral of the story? Don't make teenagers fight a grown up's battle. They'll inevitably miss something.
Namely, the last horcrux, and the bone-chilling, undead contingency plan.
And time passes. The resistance fights a losing battle, more people become undead members of Voldemort's army, and the remaining members of the Defence Association desperately search for a way out of the hell they've found themselves. There are stacks upon stacks upon stacks of research materials - the Potter, Black, Bones, Lovegood, Greengrass, Malfoy, Longbottom, and Hogwarts libraries, and then some - and no one is spared in the endeavour.
Perhaps predictably, their salvation is found in an obscure text deep within the Black collection. It's found by Daphne Greengrass, and modified by the brightest minds they've got.
Arduously long months later, wherein they've lost even more compatriots and Voldemort has gained even more ground, nine companions gather in the Black Manor ritual room, surrounded by a runic array that makes Harry's head ache just looking at it. It's a full moon, it's Samhain, and Voldemort is knocking at their door.
Metaphorically, of course.
In all actuality, he's hammering at the wards with all the power he can spare, and the others - those not going back - have vowed to lay down their lives to grant them as much time as they need.
It's humbling, but as Blaise Zabini nods that they're all ready, and as Harry and Neville begin to funnel their magic into the arrays before them, Harry can't concern himself with what goes on beyond the chamber. Instead, he starts up the chant, and the others follow suit. Magic swirls around them, bats at their clothes and steals their voices, and then, there is nothing.