As ultra-advanced AI surpassing human intelligence emerges, entities that humanity has yet to fully grasp—constructed from materials far beyond human technological reach—begin to appear. Lacia, an hIE outfitted with a black, coffin-shaped device, is one such being. In a classic boy-meets-girl scenario, 17-year-old Arato Endo experiences a fateful meeting with the artificial Lacia. What was the purpose behind the creation of these artificial beings? Amidst questions concerning the coexistence of humans and these artificial entities, a 17-year-old boy makes a decision...