Twilight failed to tell Celestia that Cerberus, the guardian of Tartarus, had left his post all those episodes ago, only now has Celestia realized the threat to her Land, and has taken drastic action to stop it. She decided to release Discord and have her Elements of harmony teach him about the Magic of Friendship, so that he could deal with them.
Also, psychic Gummy is helping him for community service.

..A random thing I felt like writing, this is where all things ridiculous that spew from my brain will be kept, tamed, and then let loose in the Pacific ocean.
A cover image would be welcome.