The last time Luna had a sleepover, she and Cthulhu had a pillow fight. The time before that, she played board games with King Kong. And before that, Godzilla joined her in some pranking. Her next sleepover guest, albeit not from this universe, is kind, gentle, and selfless, ally to good, nightmare to evil. Celestia finally feels Canterlot can stand an event planned by the Moon Princess. That is until the uninvited guest arrives. Property combusting, subjects screaming, and lots of flashy lights. Add to the fact that the ambassadors of Las Pegasus are visiting to discuss new economical arrangements in 16 hours, Celestia has quite the challenge set ahead of her.