Following Princess Luna's return to Canterlot, Princess Celestia had hoped to return to a joint rule with her sister. But Luna, torn by guilt over her past actions and lost in a world that has changed so much since her banishment to the moon, has locked herself away in seclusion and depression. As her concerns for her sister grow, Princess Celestia calls upon one little pony, whose mindset just happens to be a few centuries behind, to reach out his hoof in friendship. Perhaps the magic of friendship could again save her sister from herself?

Sequel to Rocinante, Pony of La Manecha