Magic is what makes life easy for unicorns. Magic helps them perform their duties and support others in their everyday lives. But sometimes, it has consequences. Consequences that are almost impossible to fix.
For Twilight Sparkle, a mistake in a relocation spell rewrote the history of Equestria. There is no sun or moon. There is no Celestia or Luna on the throne. There is no magic. Now, Twilight has to find a way to undo what she has done, and the only answer lies over the horizon, after the slim trace of burning light.