Retirement is a scary concept when you've barely had more than a day off at a time for over a thousand years. Doubly so when it's not physical or mental infirmary driving the decision. For the former princess Celestia, everything that has happened has sparked what was supposed to be a small, casual adventure, but as per usual, nothing is as simple as it's supposed to be.
A chance encounter and a cry for help puts Celestia face to face with an otherworldly affliction that endangers not only the Breezie village where it seems to have originated, but potentially all of Equestria should it spread. Cut off from the allies she normally relies on, Celestia must instead rely on her intuition, wits, and leadership to battle an enemy she can't even see, or else succumb to the will of this dream from beyond the void.
A crossover with Hollow Knight, with spoilers for the ending of that game, though knowledge of the game's story is not necessary to understand this story.