The Potion Master's Second Chance (джен)

Seven months into Severus Snape's term as Headmaster, he finally perfects a potion that could change the war for the better… or destroy everything Dumbledore set in motion before his death.
Dumbledore is dead, and his plans seem to be falling apart before Severus' eyes. Harry Potter and his friends are no closer to finding and destroying the Horcruxes, and Voldemort's hold over the wizarding world is growing. Severus Snape desperately creates a potion that can send him back five years into the past. Hopefully, with more time, he can find the Horcruxes, find a way to save Harry from the Horcrux inside him and maybe even save some of his other students along the way.
Or he could fail and doom them all.
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Please see series notes for a more complete synopsis and an update on the rating.
TW for the series: As of Chapter 86 in December 2023, the rating for this fic has been updated to M from T. For the last half of this story, there have been more and more fight scenes and deaths, and I have felt like I have been toeing the line, so finally increased the rating. All problematic scenes have TW at the start of the chapter so the reader can skip scenes if they wish.