Following the demon-beasts' defeat in the Great War, the empire now dominates the world through the perpetual utilization of aer to uphold their prosperity. Recently enlisted Imperial Knights, Yuri Lowell and Flynn Scifo, are tasked with investigating abnormal aer activity in the town of Ceazontania. The area is under serious threat due to the abundance of mutated beasts. In the capital, the Supreme Commander of the Knights, Alexei Denoia, and the inexperienced Princess Estellise, engage in a power struggle in secret. Meanwhile, the Knights stationed in Ceazontania are left without immediate support from the capital, exacerbating the situation. Unexpectedly, Niren Fedrok, Commander of the Imperial Knights in Ceazontania, makes a life-changing decision for Yuri and Flynn. Will they be able to unravel the secrets behind the unusual occurrences while defending the innocent people of Ceazontania, all while holding on to their beliefs?