Takes place after Rainbow Rocks.

Discord is an young troublemaker. That's what got him kicked out of a few schools. Now, he arrives at Canterlot High with one last chance, and what's more; he has chaotic power over reality. His goofy attitude makes him an easy target of distrust from a few students, especially the callous, stubborn, and strict candidate for student body president: Starlight Glimmer.

I could've chosen a better story image, but I couldn't find anything for a young Discord. Besides, this image symbolizes a certain element in the story.