On the eve of Hearth's Warming Eve, as Luna raises the moon, she is visited once again by the very entity which drove her to madness. Resisting it's influence, Celestia and Luna hatch a plan to end this once and for all.
One which works too well with unforeseen consequences.
As the nightmare loses it's power, it plummets to the earth followed by an explosion of Power that the Royal Sisters know too well. However when they find the epicentre of the explosion they are shocked to see an Alicorn with no memory, and no name.

Yet the question remains. Why does it resemble Luna so much that they could be twins??

Follow the story as this unnamed Alicorn makes her presence into Equestria, for better or worse.

After Nightmare Night, Luna invites Twilight to tea, and they start spending more time together. Princess Celestia teases Luna about it sometimes.

After many failed attempts to defeat his mortal nemesis the Pharaoh(AKA Yugi Moto) Marik along with his (reluctant) partner in crime Bakura, sneak into KaibaCorp Headquarters in order to use a machine previously used during the virtual world episode in season one. However, thanks to the unexpected appearance of Jack Slenderman, Marik and Bakura, to his utter dislike, find themselves in the world of Equestria. Now the two ga- da I mean partners in crime must work (somehow) with the mane 6 on getting back to their world, along the way face a great evil the mane 6 thought they had defeated.

A crossover with Yugioh Abridged done by LittleKuriboh (CardgamesFTW is his youtube account, watch it if you haven't) and MLP:FiM. The picture belongs to Twilight-Angel93 on deviant art