The Summer Sun Celebration is here and it's being held in Starlight Glimmer's old village!
Starlight Glimmer is sent to there by Twilight Sparkle and is instructed to check on the preparations. There, she meets new ponies that had moved there and are in charge of the preparations.
Just when the sun was about to rise by Princess Celestia, she was nowhere to be found! Not even her sister, Princess Luna, was seen, either!
Then chaotic things start to happen. The dirt road turned soapy, the moon turned into cheese, houses grew wings and flew away, and clouds turned into marshmallows that rained strawberry milk. This could only be the work of Discord. Only . . . it isn't.
Who could be the one causing chaos?