The CMCs have gotten a rather annoying homework assignment. The three must write a report on an important event in Equestria's history. After drawing a blank, the three go see if the local egghead Twilight can help. Said egghead tells them the story of a great war that happened before Celestia's reign, a war that could have completely changed the face of Equestria entirely. This is the story of the Horsican wars.