Having been isolated from outside influences for over two thousand years, Equestria is abruptly invaded during Celestia's absence from Canterlot while she is meeting with important individuals elsewhere. Though the six bearers of the Elements of Harmony initially find help within Equestria, they are ultimately unsuccessful in repressing the trespassers and the situation soon turns far too dangerous for them to remain in their home. Leaving the familiar limits of Equestria for the first time, as few ever have, Twilight and her companions have only one course of action in the unfamiliar world that lies "out of bounds" if they wish to save their home: making new friends.
P.S.: I'm deciding whether or not these will go into the completed story, so bear with me.