Twilight Sparkle Gladly accepts Princess Celestia's invitation for a week-long visit, hoping to be able to bond with her former teacher and be as close to her again as she had once been as a filly. As the week goes by, Twilight notices that Luna is becoming more distant. Luna eventually voices her troubles to Twilight, a dream revealing a forgotten dark secret about her sister, and warns Twilight to be cautious around Celestia. Twilight dismisses Luna's suspicions as jealousy, but is that really all there is to it?