Luna and Celestia have settled their differences. With one major obstacle settled, Equestria and the Lunar Republic are coming back together as allies and partners. But danger still lies ahead, and not all are happy with the new arrangements. More challenges await the Royal Sisters, along with Twilight Sparkle, Sunset Shimmer and their friends, as the world continues to change.

Second in the Worlds-verse, and a part of the greater The Powers That Be multiverse.

Has a TV Tropes page here.