When Rarity woke up, she noted two things. Firstly, she saw that Pinkie was already awake, staring out of the window into the sky. And secondly, she noted the colour of said sky.
Celestia is a spider. Celestia remains a spider. And we-Well, we didn't really have anything to do with it, but we're still the ones who have to suffer the consequences.
The Crystal Empire has returned, along with its tyrant, King Sombra. It is up to Twilight to save the Crystal Empire, and she does exactly what is expected.
Discord finally escapes his stony prison, but he's got a proposition for Twilight. One that will either see him reformed, or as the ruler of Equestria.
Upon waking up one day and finding out that she'd become a spider, Celestia had reacted in a surprisingly calm manner, simply deciding to inform her subjects of the fact. Chrysalis, unfortunately, had not been among them. It disturbed her greatly.
Torque finds herself in unfamiliar territory of welding. Not only she has to work with a metal she is unfamiliar with, the part also has to be perfect. But, for what reason?
Tirek has returned, and he wants all of Equestria's magic. Twilight won't let him have that, and she is the final obstacle between him and world domination.