Aquamarine and Garnet are both members of Queen Celestia's Solar Guard. One day they get summoned to her study to get a new Assignment, from the Queen herself, to create a regiment of Royal Guards for Princess Twilight. Thats how the Orion Guard is born. Now Aquamarine and Garnet are tasked with commanding this new regiment and protecting Princess Twilight and the Council of Harmony from a dark force brewing in the forbidden Shadow Lands.