This story is a sequel to The Blue Mage
When Apple Bloom, Daring Do, and Trixie discovered an alicorn prison dating back to the time of the alicorn purge, they were shocked to find it held two seemingly innocent alicorn fillies. Leaving them with Twilight, Spike revealed that they weren’t just any alicorn fillies; they were the daughters of the most dangerous alicorn to ever live. Now they must find their way in a world far different from the one they knew.
Meanwhile Twilight, with the help of Daring Do, begins checking on the remaining alicorn prisons that are hidden throughout the land, both within Equestria and beyond.
This story follows directly after The Blue Mage, and has a lot to do with the Alicorn Imperium and the Alicorn Purge that was introduced in Child of Misery, so reading both will be necessary for this story.