In the war-torn realm of Aionios, two hostile nations—Keves and Agnus—wage perpetual conflict using soldiers engineered to live only a decade, their brief existences spent fighting to sustain their homeland's Flame Clocks. Among these conscripted warriors are off-seers like Noah and Mio, soldiers tasked with ceremonially honoring the dead through haunting flute melodies, each commanding their own devoted squad. When their opposing units collide and are devastated by a cataclysmic force, an enigmatic phenomenon known as Ouroboros mysteriously intertwines the survivors' destinies, forcing former enemies into reluctant partnership. Now hunted as traitors by both nations, the unlikely band of allies must venture into the unknown to expose the buried origins of the conflict grinding their world into oblivion.