Set some years in the future, Rarity is a mare just on the edge of her prime. She's still alone, but that's not a bad thing - she's had a long and successful career, with many illustrious lovers. But these days she's feeling a bit lonely. Not that she can't find a partner for her bed - her feminine wiles are as sharp as ever. There's just a craving for something more.
And then Twilight Sparkle pays her old home a visit, with her former assistant tagging along. Spike has grown up a bit, an adolescent in dragon years. And he's got a few things he'd like to confess to Rarity.
Smoking hot dragon-on-mare sex ensues.