This was inspired by the movie Goodbye, Lenin.

Twilight Velvet, avid supporter of the Equestrian monarch, has a near-fatal heart attack from seeing her daughter beaten and arrested during a protest that should've never come to be. She falls into a coma, and Princess Luna returns to the throne during her sleep. With the doctors saying "No Surprises," it is up to her family to prevent her from finding out that Equestria is now a diarchy, so she doesn't have a second, possibly fatal, attack.