Lethat Flier has had a tough childhood. She was abused, and she was seen as a disgrace by her family. She started shunning them herself, and one day when she was practicing dark magic, she earned her cutiemark but also two wings...
She earned some type of recognition from her fellow ponies but one day disappeared of the face of Equestria.
Years later, she returns with an army, and is ready to take down the wrongful leaders.

Meanwhile, Spike is shunned by everypony including the main six after the greed incident. Lethal Flier sees this, and takes him in to her cause. There will be a long war and a lot of devastation, will the four alicorn princesses defeat the angry alicorn and will the main six including the rest of Ponyville be able to apologise to Spike?