The Dazzlings have won. The Rainbooms failed and the sirens have regained their true forms. The world is theirs, but first they have to make sure that it remains that way...
Sunset Shimmer finally returns home to Equestria to right her old wrongs, unfortunately the sins of the Human World follow her back and put everypony in Equestria in danger.
A year after the battle of the bands, graduation nears, a familiar face returns, a pure heart is corrupted, enemies become allies and the fate of all reality hangs in the balance.