When Princess Celestia comes down with a mysterious illness despite her immortality, her loved ones flock to her side, including Sunset Shimmer. With only so much time left, Sunset takes it upon herself and Twilight to get to the bottom of it. The two of them work together non-stop to find a cure, which would be fine, if Sunset had gotten around to telling any of them she's dating the other world's Twilight.

Edited by the kind and insightful Space Jazz. Cover art designed by the incredibly talented Kiki-Kit and modified by the masterful Amber Spark! Spoilers in the comments.