Princess Luna's Lunar Stallions kidnap Twilight Sparkle when they see how lonely Luna is, and give her to the Princess as a gift. Nightmare Moon emerges from Princess Luna's psyche during the sleepover. The dark goddess would love nothing more than to have the beautiful mare all to herself, and the resulting chaos forces Celestia to call a psychologist to sort out Luna's multiple personalities.

Luna takes a personal day at the request of her sister and Twilight Sparkle, but whilst visiting they each find something hidden in their hearts they didn't know was there....