This is a rough idea but i figure since Luna only appeared 3 times i feel as though there should be some development in her story
So it start at Canterlot castle Luna is walking around the castle remembering how it felt the last time she was here. She explores various of places of the castle remembering funny and happy moments, than she stumble the area where she turned against Princess Celestia It was the main hall where Celestia sat and held meetings. Anger and sadness started to arise and she turn away from the area and flew away from the Castle. A few days passed and no one heard or saw Luna Twilight was assigned to bring Luna back and uncover what had happened. Their only lead to her whereabouts was provided by none other than Derpy who could see in two directions. With that the Gang set out to find her, they wont realize how dangerous the mission until it is too late.
again it is said to be a idea board so that's it if you have comment let me know, i might plan to write a bit more ideas if this is good.
So it start at Canterlot castle Luna is walking around the castle remembering how it felt the last time she was here. She explores various of places of the castle remembering funny and happy moments, than she stumble the area where she turned against Princess Celestia It was the main hall where Celestia sat and held meetings. Anger and sadness started to arise and she turn away from the area and flew away from the Castle. A few days passed and no one heard or saw Luna Twilight was assigned to bring Luna back and uncover what had happened. Their only lead to her whereabouts was provided by none other than Derpy who could see in two directions. With that the Gang set out to find her, they wont realize how dangerous the mission until it is too late.
again it is said to be a idea board so that's it if you have comment let me know, i might plan to write a bit more ideas if this is good.