On an evening warm and fair, Princess Luna comes walking to Twilight's castle, singing as she goes. Twilight, however, is not there to meet her and so Luna believes she's been stood up. Then she discovers that something far more sinsister has happened, for Twilight, picking flowers for a bouquet at the edge of the Everfree, has stepped into a fairy ring on Midsummer's Eve.

(Continuing my habit of basing stories on songs.)