After the events of Hurricane Day go horribly wrong, Fluttershy finds herself alone near the mythical city of Atlantis. On a search for her friends, Fluttershy decides to trust a stallion named Sun Streak and his group of friends as, as he likes to say, they don't leave Drifters behind.

Unfortunately, after reaching their destination after a long trek through neighboring hostile cities, they find themselves right in the middle of a siege upon their home. As Fluttershy learns of terrible secrets having to do with both the city she's trying to protect, and herself, she must ask herself: is it worth it? Should she continue to help these ponies even though they're just figments of her imagination?

Meanwhile, Twilight and Rainbow Dash are on an adventure of their own, searching for the magical item that will bring their friend back from her coma.