The daughters of Luna and Celestia- A MLP fanfiction

**this is my first fanfiction, so I hope you like!**
It's been ten years since Twilight Sparkle and her gang of ponies last saved Equestria. The wrongdoings and crimes that once flooded the land have since subsided. For now, we turn to a different part of the story, one that involves Princess Luna and Celestia. This book although, is not about them; it's about their daughters, Princesses Brightsummer and Winterstar. After ten years of reprise, Equestria is facing danger again. Possibly, it's the worst it's ever faced, and it doesn't seem that the Mane Six are up to the task. Upon hearing this, the two young daughters attempt to set out on a life- threatening journey to save Equestria-- one, it seems cannot be done without help. But, who said they were going alone?