Harry Potter: Backstep

On the verge of losing the war, Voldemort tries a final gamble - an esoteric ritual to send himself back in time. Luckily, Harry Potter manages to stop him, but he's thrown back instead. Arriving right before Voldemort's rise to power, how will Harry manage to save the people he loves, stop Voldemort, and change the future for good? Harry/Multi. Smut.