On the eve of the Summer Sun Celebration, Sunny Starscout realizes an ancient evil is on the verge of returning. Now it’s up to her to stop it; if only she could find the mysterious artifacts known as the Elements of Harmony.
(Spoilers for Make Your Mark: Chapter 4.) While still adjusting to life in Maretime Bay, Misty happens to bump into Sprout. As it turns out, Sprout knows something about what Misty's going through. In fact, he's had a similar experience.
(Loosely based on "Winnie the Pooh and a Day for Eeyore".) Sunny becomes convinced that Sprout feels like he's been forgotten, so she decides to cheer him up by having her friends work with her to throw Sprout a surprise birthday party.
Sunny and Hitch learn that a dragon named Spike was responsible for sending Sparky's egg to Maretime Bay. They and their friends then seek out Spike to try to get some answers about what happened to Equestria and Princess Twilight.
Hitch Trailblazer comes out of the Maretime Bay PD to do his afternoon rounds with his deputy only to find the populace in a panic. Quickly finding the source of the hysteria, it's time to put Canterlogic's defenses to good use...
(Based on a fan comic.) Sprout runs away from Maretime Bay and makes an unusual "friend". Said friend convinces Sprout to turn on his other friends. When things look bleak for Sunny and the gang, some unexpected faces show up to help.