This story is a sequel to Past Sins

Side-story to Past Sins - Spike almost lost Twilight to a hangmare's noose, but now Twilight is safe and Nyx is a filly again. Normal life is returning. Still, Spike can't ignore the fact that Nyx just isn't the same as he remembers her. Her temper is more volatile, and, when she gets angry, all he can see is the rage-driven Nightmare Moon of legend.

And thus Spike has to wonder: Is Nyx truly reformed, or is she one bad tantrum away from calling herself Nightmare Moon again?

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?