The map has called Celestia and Luna for their first ever friendship mission together. Where is it sending them: To a place called Skyros, a kingdom of alicorns. It's a place that nopony but the two sisters have ever heard of, because it's the place they were born and where they lived before coming to Equestria all those years ago.

The former royal sisters are quite surprised and concerned, but nevertheless are not about to disregard a summons from the map. However, what they discover upon returning to Skyros horrifies them!

Skyros is preparing to declare war on Equestria, believing it to have kidnapped the royal sisters so long ago. Celestia and Luna must now utilize all the diplomatic skills they learned from their many, many years of ruling, and try to get the land of alicorns to see reason before it's too late.