Takes place after S9 E25,
The Ending of the End (P2)

Note: Involves Twilight x Starlight

Princess Twilight Sparkle discovers how to travel further back in time than Starswirl the Bearded -- with the help of her former foe and student, Starlight Glimmer. After traveling farther back than she intended, Twilight discovers some truths about Starlight's past that she was not shown prior to the mare's bittersweet reformation. Her discovery leads her to an overprotective obsession with Starlight and her past, and results in Starlight's attempt to reform a villain like herself.

Cover art drawn by myself.