Three hundred years into the apocalypse, I live in the paradise-like Ark City, humanity's last sanctuary. Then an accident awakens an ability that lets me see the true nature of things. The “Guardians” we revere as gods are monsters made of writhing flesh and tendrils; the nutrient paste we depend on for survival is made from our fellow humans, who supposedly “died peacefully of old age.” How is this a sanctuary? It's a slaughterhouse where we're penned up like livestock! The angels who patrol every day are executioners coming to claim our lives; their merciful teachings are lies meant to numb us. As the only one who knows the truth, I must pretend to be the most devout sheep if I want to survive in this heavenly hell. But I have only one goal: escape, and tell the whole world.