As ponies live out their lives, they experience many things that will stay with them forever. However, as they grow up, the only thing that they can do is look back on those memories and can never truly experience it for a second time. Twilight has grown up drastically since she left the comforts of the library in Canterlot behind and she wont rest until she returns to a place that made sense to her. Looking back at her old self to get a better perspective as she looks forward at her current self.