The mirror held in the Crystal Empire opens once every 30 moons to Canterlot High. At least it did.
The mirror has started to open once every five moons but not to Canterlot High. It opens to a completely different world. Celestia has created a colonization effort called Equestria Nova to establish a presence in this new world. Ponies from across Equestria have been selected to start a new life here. However, they soon discover this world works very differently from Equestria.
Proofread by Caden who also did the cover art.