Everything Happens For a Reason Part One- The Return

As Princess Celestia reached the window just after the shadow pony. Seconds before Celestia, the shadow pony snuck in through a gap in the ever-so-slightly-open window, and slammed it shut! Celestia had been barred out with magic! The pale blue magic reminded her of somepony... As Luna slumbered the shade-pony revealed itself wings first, then horn... wait, an Alicorn!? that didn't make sense...