Cadence is elated for her upcoming wedding day, and takes advantage of a sunny morning to deliver special wedding invitations to the elements of harmony. But her perfect day takes a slightly confusing turn as she experiences headaches, hot-and-cold sweats, and magical overload.

It's not until she reaches the door of her sister-in-law, Twilight Sparkle, that she realises that her problems might be far, far more personal then she'd like.