Twilight has fallen ill with a seemingly incurable disease. As Rainbow Dash keeps seeing flashes of her life with her, she is more than determined to save the life of the one she loves, even if she has to lose herself for it.
Twilight gets bitten by a spider when she was doing a task for Zecora, then when she was experiencing the symptoms, she goes to the doctor and learns she has a fatal disease and only a week to live.
When Misty discovers Senor Butterscotch, she asks Izzy about why she created the fake unicorn. Izzy reveals it all stems back to her childhood in Bridlewood.
(Spoilers for Make Your Mark: Chapter 4.) While still adjusting to life in Maretime Bay, Misty happens to bump into Sprout. As it turns out, Sprout knows something about what Misty's going through. In fact, he's had a similar experience.
In a quiet club nestled within the depths of Canterlot, a returned Sombra ekes out a life as a bartender. The woes of a moonlit mare may prove, however, that fate has more in store for a former King; and that a heart of stone may not always be so.
Gilda comes to Ponyville, hoping to reconcile with Fluttershy. Fluttershy, though surprised by Gilda's sudden appearance, agrees to hear the griffon out.
Ponyville Hospital is about to get a very important visitor. Why is she there, though? The full harrowing details are about to be revealed... Set just after Twilight's Kingdom.