The Potion Master's Second Chance (джен)

Seven months into Severus Snape's term as Headmaster he finally perfects a potion. This potion could change the war for the better, or it could destroy everything Dumbledore set in motion before his death.
Dumbledore is dead and his plans seem to be falling apart before Severus's eyes. Harry is no closer to finding and destroying the Horcruxes and Voldemort's hold over the wizarding world is growing. In desperation, Severus Snape creates a potion that can send him back five years in time. 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.