The end-of-the-world war erupts thirty thousand years in the future. Galzeria launches a powerful military force to destroy Sphirna. At the heart of this war stands Sphirna's king, Anthem, who detects that the enemy commander, NARITA, exists in Earth's past—specifically, in the modern era. In response, he dispatches the assassin known as Crescent Knights. Crescent Knights is Yuriya, a Japanese schoolgirl born and raised on Earth. Unaware of the war, she has been living an ordinary life—until one day she suddenly receives an emergency signal from Sphirna thirty thousand years in the future, heralding the start of battle. But Galzeria counters by sending General Schwalme, who captures Yuriya, leaving her trapped and facing utter humiliation and despair...!