A strange infection is spreading across Equestria. Mysterious cloth-like ponies have appeared and any pony they touch becomes a mindless husk. As the disease threatens Ponyville Princess Celestia sends Twilight Sparkle and her friends on a desperate mission to meet up with an old friend of hers, Shadow Tempest, to have a cure made. At the same time, Apple Split begins to uncover a secret Soarin has been hiding from him. What Care Package had done to him during Operation Lost Cause.
