In a world divided by loneliness, two enemies discover a shared struggle amidst a battlefield where death is but a temporary setback. Within the relentless conflict of warring factions, teenage soldiers wield the unparalleled power of 'Arcadia,' a revolutionary life regeneration system. These resilient youths, branded as 'children who transcend death,' face off in an endless cycle of demise and rebirth. Akihito, a skilled leader in the United States Army, finds himself tasked with a crucial mission after a series of setbacks. Forced into a dire situation with his rival, the elite Federal Army girl Philia, deep underground where regeneration falters, they must set aside their differences to survive. Despite their clashing personalities and abilities, Akihito and Philia must unite to navigate the unforgiving battleground and reclaim the surface. Thus unfolds the tale of their unlikely partnership amidst the unending war that defines their existence, a narrative woven with encounters and resonances that refuse to fade, earning acclaim as the Gold Award recipient of the 28th Dengeki Novel Prize.