Incantus was an old foe of Celstia's and an immensely powerful unicorn mage. After taking over Ponyville in a matter of minites, he proceeds to kill, well, everyone.

This will get more teen oriented later, but this is just the beginning. The mane six are thrown into an alternate timeline where each of them works for or supervises a company. The three corporations are waring, and all the mane six have to do is run home. Easy?