Fixed in Time (фемслэш)

"I did not want this for him, for my son. I did not want...any of this," the words poured from her lips like bubbling potion boiling over, "I wish...I wish I never allowed him to set foot on this path. That I never stood by and let the Dark Lord brand his precious skin with his Mark…I wish for many things Miss Granger. If I could change the past, I would.”
A desperate plea leads to a desperate mission. In a split second when all seems lost, Hermione Granger, Gryffindor’s Golden Girl unlinks the golden chain around her neck and throws it around the shoulders of Narcissa Malfoy and turns back time to a week before Draco was set to take the Mark. Working together they'll manipulate the events of the last few years to lead their past selves to victory against the Dark Lord. They have a year and a half to change the course of Draco's life, destroy the Horcruxes, prepare all versions of themselves for the Final Battle and make certain their past selves still end up in Malfoy Manor so they can snap back into time without creating a major paradox.
A lot can happen in a year and a half.