I wasn't exactly expecting anything to be wrong.
Shining Armor had gone to bed and I was still awake, unable to sleep. My aunt Celestia had offered to help with my wedding plans, and I'd accepted, but that didn't mean I wasn't stressed. I'd snapped at the seamstress taking my measurements for a dress and still felt kind of bad about it. I was only marrying the best stallion in the world...I shouldn't be freaking out so much.
But the truth is that everything was going perfectly. Celestia had found a wedding party, since I didn't have any friends in Canterlot after living for several years with distant relatives in Saddle Arabia. There had been a threat against Canterlot made from an unknown source, so Shining had been occupied with his constant protection of Canterlot, and he'd been getting terrible migraines, leaving the planning part of the wedding to me and my aunts. But other than the nervousness caused by the threat, everything was going just fine.
So I wasn't expecting anything that night when I was taken, or it might not have happened at all.
A servant came up to me that night and told me my Aunt Luna needed to see me right away. I naturally followed, I didn't suspect anything wrong with my Aunt wanting to talk to me about my wedding. Luna had already told me that she would not be in Canterlot for the actual ceremony, she was flying to the other major Equestrian cities to see if their mayors had received any threats similar to Canterlot's and her duties as Guardian of the Night prevented her from doing that at any point other than during my wedding. But my Aunt was concerned about me over stressing myself and there was nothing unusual about her trying to get me to go to bed.
It wasn't until I realized we weren't headed to Luna's chambers at all that I noticed something was wrong, and by then it was too late. The servant changed into an insect thing that trapped me with a green slime. It then changed back into the servant and bowed as another, taller insect thing came around the corner.
"Princess Mi Amore Cadenza, how lovely to finally meet you in person," the thing said. I shivered as her, this one was definitely female, washed over me. "It's a shame we Changelings won't have time to get to know you better, we have a wedding to crash and a world to take over."
A wedding to crash? Oh no she did not.
"I don't know who you are or what you want with me, but you're not going to touch my wedding!"
"Oh my dear princess, it's not going to be your wedding!" she said.
Then, before my eyes, she transformed into...me.
"It's going to be mine!"
A glowing green light surrounded me as I struggled to escape the slime, and her...my...evil laughter echoed around me as I sank through the floor. The last thing I remember before darkness surrounded me was shouting Shining Armor's name and hearing her cackle back.