The princesses gave their magic to Twilight to prevent Tirek from stealing it. As a result, they end up stuck in Tartarus. The fact that things manage to go downhill here says a lot about the wonders of family.
When musical mayhem threatens Equestria, the brave and misunderstood ponies of the Versebreakers are on the job. Ten music-themed stories by eight talented authors.
Twilight discovers that a new tea shop has opened up in Ponyville with an owner a bit on the tyrannical and overlordy side. However, business seems to be booming, even if the proprietor is still totally evil... with his prices!
Sonata is left alone in a supermarket by the other Dazzlings. Presumably left for dead, she’ll have to pull together all her survival skills to if she’s going to make it on her own.
How would a being like Discord want to be remembered after he's gone? Well, if you're curious, he did actually write a will. To the surprise of nobody, its contents are bizarre and mildly disturbing.