On a dark night filled with even darker magics, an insane cult attempts to give Nightmare Moon a body and life of her own, utterly separate from Princess Luna. But, when the spell is interrupted by Celestia, something unexpected is created.

Now, a little black alicorn filly named Nyx finds herself living under the care of Twilight Sparkle, only to be haunted by memories and emotions from her past. Is she Nightmare Moon reborn or is she simply a doppelganger with a soul and mind of her own? Can Twilight Sparkle protect Nyx from those who refuse to see past her dragon eyes and black coat?

Or, will Nyx be forced to inherit the sins that may not even be hers and become the greatest evil Equestria has ever known?

It has been 2 years since King Sombra tried to over throne the Crystal Empire. But when the Mane 6 are invited to the Empire's Grand Galloping Gala, This Gala takes a surprising turn. When Twilight goes missing, it is in the Mane 6- er, 5, hooves to find Twilight, and see what is lurking beneath the Crystal Empire. But one question remains--
Will they find Twilight?

Cover Picture; By Myself
Written By; Myself. Wow. I'm pretty independent.

This story is a sequel to A Stitch in Time

Having discovered the message left for her by Star Swirl the Bearded in the distant past, Twilight once again finds herself caught up in the middle of a struggle against forces far greater than herself. In order to even stand a chance she'll need to travel further and wider than she ever has, and forge some unlikely alliances with old enemies. All to bring down the powers that have manipulated and shaped her entire life, and retake control of her own future.

The conclusion of the Time Loop Trilogy, which began with Hard Reset
Available in Spanish thanks to dgs1993
Series TV Tropes page

The world was left without magic after the Discordian wars. Twilight, a budding new student of Princess Celestia, manages to form a spark, the first magic in two thousand years. With Celestia's training they hope to bring magic back to every unicorn in Equestria.