You compromised on the location.

You'd been away from Equestria for so long, after all. It didn't feel [i]right[/i] to drop so suddenly back into high-society Canterlot. You had envisioned a small ceremony, a simple affair in the little earth pony village you grew up in. You'd even picked out the perfect, cozy little bower. Just you and Shiny and some close friends and family.

Aunt Celestia quickly shut that idea down. "You are a princess, [i]Mi Amore[/i]. You are marrying the Captain of my Royal Guard. This will be an affair of state." Her tone of voice did not brook disagreement. A formal wedding it was, then; directly on the castle grounds.

You compromised on the dress.

You'd paged through all the bridal catalogues. It was all lovely, of course; yards and yards of silk and lace and chiffon, nothing to spark the imagination. But the photograph of the bride who approached the altar wearing nothing but her own coat of fur and a few wreaths of yellow roses caused your breath to hitch in your throat. "A Natural Wedding!" the caption had crowed. [i]Yes[/i], you'd thought. [i]This one. This is it.[/i]

Naturally, it was decided that you would wear a proper bridal gown. The designer was Rarity of Ponyville, a smart, chic, up-and-coming young designer who also happened to be a national hero and savior of the realm. You quietly suspected a bit of tit-for-tat—broad exposure of your work at the wedding of the century in thanks for pulling Equestria's chestnuts out of the fire—but no friend of Twilight Sparkle's could be all bad, right? So you boxed your own idea up and put it on a high shelf and quickly stopped speaking of it. Raising a fuss was never the polite thing to do. It was unbecoming, you thought, of a pony of your station.

You compromised on the bridesmaids.

Diamond Rose and Lemony Gems, your old friends from Academy! You hadn't seen them in years! Certainly, they would be ideal; but before you'd even had a chance to mention their names you were informed that a trio of proper court mares had been selected for the ceremony, and that was that, you guessed.

Perhaps it was inevitable that, at the end of this road, somepony had taken your very identity from you, and the groom—your beloved Shiny!—along with it.

So, there you sit, in your miserable crystal prison, listening to the chitinous abomination titter to herself about her flawless ruse. How she—even though none of it ostensibly even [i]mattered[/i] to her—had loudly demanded, and gotten, the dress she wanted, the cake she wanted, the entertainment she wanted. Somehow, the monster had received everything her black heart desired, down to the smallest detail. When she approaches the altar tomorrow, her face will be the only false thing about her.

Your heart quails for the future of Equestria, and for the fate of the poor stallion you love more than life itself. But for the first time since this terrible ordeal began, an odd and treacherous thought crosses your mind:

Which one of you is truly the impostor?