That wedding, what happened; it doesn't add up. It's all too convenient. The spread-thin forces, the Changelings picking away up above, the Queen getting in. Something isn't right here...

Delta return to Equestria to save Twilight from two old enemies

A long time ago, Twilight Sparkle DID have friends. Twenty of them, in fact. Her closest of the bunch: Delta Spell, finds out that she sold them all out, and got all but two of them killed.