After their last adventure, Apple Bloom, Sweetie Belle and Scootaloo give up to their inner tension and their friendship cracks up. They even wreck their own clubhouse in the fight, the final hit, and the team disbands, leaving each filly alone by themselves. However when their big sisters Apple Jack, Rarity and Fluttershy, as well as the other Mane 6, lose their talents and Cutie Marks to an ancient evil that Celestia herself failed to completely defeat 500 years, the former friends must leave their anger and issues behind and head towards past beyond the Everfree Forest into the unknown Mythic Forest. It's the ultimate adventure and maybe the last time the CMC will be together.