Long ago, Equestria was ruled by King Cosmos and Queen Galaxia, two kind monarchs who loved their land so much that their devotion to Equestria ultimately left their two young daughters orphaned and alone.

The sisters’ most precious belongings were left behind when Nightmare Moon was banished. On the pages of two simple leather books that remained hidden in the Castle of the Two Sisters for millennia, the princesses describe in detail their happiest moments alongside the daily struggles of their adolescent years. They also express their deepest fears as they face the looming threat of war and the pain of losing their parents.

Celestia’s increasing indifference towards the pony who needs her the most serves as the catalyst for Luna’s heartbreaking descent into darkness as she continually pleads for her big sister’s love and attention. The growing tension between the sisters is documented through the eyes of the princesses themselves.