A decade ago, alien entities called Kikou descended from the sky and began a relentless assault on civilization. Now humanity fights back with an unconventional weapon: a mecha constructed from the corpse of one of these invaders. Pilot Mizuru Mido and her support specialist Fuu Sagami form an unlikely pair tasked with defending what remains of their world, but victory comes with a devastating cost. Every time Mizuru engages the enemy, fragments of her memory vanish. Each battle leaves her more fractured than before, raising an urgent question: is this biological consequence of piloting a corpse-based machine, or something far more sinister? As Mizuru continues to lose pieces of herself with every sortie, she and Fuu must race against time to understand what's happening inside her mind before there's nothing left of the pilot at all. The stakes climb as personal mystery and military desperation collide, forcing them both to confront whether victory is worth the price of oblivion.