A broken world in the not-so distant future. Humanity is facing a new incident. "We’re being attacked by humans who should be dead." The government has decided to request a specialized organization to deal with this situation. The Laboratory of Optics and Neural Analysis, commonly known as "LONA." Researcher Ao and her apprentice Sango will try to get to the bottom of the mystery by analyzing the brains of the dead. What do people think of, and what do they leave behind before they die? Countless memories engraved in the neural circuits. What did they see in those deep depths?