Every year Luna amd Celestia go Trick or Treating together. But this year Celestia decides she needs to stop the emberassing tradition. Luna doesnt take the news to well and decides that its about time Celestia got more im touch woth her foalish side. But the age regression spell Luna uses transforms Celestia into a foal and Luna takes the oppurtunity and goes trick or treating with the foalified Celestia regardless.

editor Zubric

Source of cover art:
Skitter