Time and reality; concepts that allow a being to measure how long it's been and the world around them. To us, they may be concrete and unchangeable but to others, they are as fluid as the ocean. One slight change in how things were done, what was said at a key moment or how things played out could change the course of history. A different choice of words, a different turn of events, a missed attack, a sudden twist, an offer that previously wasn't extended, a choice previously refused or never even possible, a decision to do or not to do something. Any and all of these can change the world forever.
In this universe, instead of kidnapping Rarity, the Nightmare Forces kidnap and corrupt Rainbow Dash into Night-time Flare. Unlike Rarity's very public kidnapping, Rainbow Dash's is whilst she is alone so the other Elements and Princesses are woefully unprepared for what is about to hit them and Equestria. What are Flare's goals and what is everypony going to do about it? In the meantime, a far greater but largely forgotten evil waits in the shadows with terrible designs for the entirety of Equus. The fate of Equus itself lies in the balance of both friends and enemies alike. It is ultimately a tale of making severe mistakes and facing the consequences. The only thing for certain is that past grievances will be faced and hopefully resolved whilst one particular ruler must face the major mistakes that she made in the past.
Timeline note; The story is set after "Keep Calm and Flutter On" but before "Magical Mystery Cure." Two years have passed since the events of the Summer Sun Celebration.