Grey Heritage Noble Duty immerses players in the year 755, when the continent of Calista is engulfed in war unleashed by Emperor Augustus. The protagonist, Jaden Rickard, Lord of Astraea, is unjustly accused of treason after abandoning his post. His mission is to cross the continent in search of allies to fulfill his duty and understand the true causes of the bloody conflict. The central storyline focuses on his attempts to assemble an army capable of stopping imperial aggression.