Sunny, Hitch, Sprout, Applebloom, and Seashell use their Earth Pony magic to heal the Golden Oak Library.  
 
You all know the infamous battle between Twilight and Tirek at the end of season 4 and the most tragic event to come out of said battle: The destruction of the Golden Oak Library. It was devastating to see it be destroyed, even just by accident. The place had a history, serving as Twilight and Spike’s home and a place of refuge in the midst of their adventures. The library also held many precious memories, from Twilight’s sleepover with Applejack and Rarity to her “Twilight time” with the CMC. But sadly today, only few remember it. Including Applebloom, now in her old age.  
 
As the story goes, Sunny and Hitch accompany Sprout to Ponyville to meet Applebloom, with Seashell tagging along due to her fascination for the historic town which she has read about in many books. Some time into their visit however, Seashell finds the Golden Oak Library and upon exploring, learns that it was the former home of Princess Twilight. But tensions rise when it is also discovered that the tree is threatened to be uprooted by the town’s current mayor, who plans to remove it as it is understandably a huge eyesore for the town. Only few ponies who know of the library’s history fight to protect it, but to little avail. Together, Seashell along with Sunny, Hitch, Sprout, and Applebloom help the town to learn the importance and significance of the tree and use their powers to heal it.  
 
Its a simple little story, the kind that you may have heard before, but that’s about it.