The narrative begins with Kibi Tsubaki, an android who died in 2030 and was reborn as an android in 2148. He resides in a fortified shelter called "Kido" for 1850 years, having taken it over from its original wealthy owner. This shelter was built in the early 2130s to withstand environmental disasters. Tsubaki's existence is a result of his cells being used for the exterior of a custom-made android. He is self-sufficient, consuming organic matter for energy, and maintains the shelter with the help of its dormant androids and a sophisticated AI named SIN.
Chapter 3 introduces Tsubaki and his solitary existence. Chapters 4-5 detail the cataclysmic event of 2150: a terrorist group called "Antis" attacked Area 51, releasing a black mist that mutated living beings into monstrous, aggressive creatures. This event wiped out rational life, except for androids like Tsubaki, whose cells were used in their construction, causing them to awaken with their former personalities. Tsubaki, a former overworked salaryman, survived due to his advanced android body, which he later enhanced with stolen military equipment.
Chapters 9-14 introduce Tsubaki's companions: SIN, the facility's AI; Magami and other W-series wolf-type combat androids, responsible for pest control; Masaru and other G-series labor androids, tasked with construction; and Torii and other E-series bird-type reconnaissance and combat androids. Tsubaki also provides a tour of his luxurious shelter, highlighting its advanced facilities, including a hydroponic farm and a meat cultivation plant, all powered by a geothermal plant.
Chapter 24 shifts focus to a lecture at the Sunrise Holy Nation's Grand University, where a professor discusses the "Demon Kingdom" and its origins in ASR 184. The lecture details the Demon King's defeat of the immortal saint Lindia, the loss of the "Amashiras" tower, and the subsequent spread of the Demon King's power and the resulting refugees.
Chapters 28-37 depict a significant turning point. After 2000 years of isolation, Tsubaki discovers humans outside his shelter. These humans, who speak an unintelligible language, are identified as "New Humans." Tsubaki's modified AI, SIN, prioritizes his safety above all else. When these humans, led by an android named Lindia (who has lost her memories of her android life and believes herself to be a human named Ashigara Suzuka), approach the shelter seeking cooperation for human development, Tsubaki refuses. Lindia's companions, Aluf and Bete, attack Tsubaki, leading to their deaths and Lindia's critical injury. Tsubaki repairs Lindia, but she retains no memory of her time as an android, only her past human life as a teacher.
Chapters 55-67 detail the aftermath. Tsubaki reluctantly allows Lindia, now Suzuka, to stay, feeling pity for her. This decision leads to a strained coexistence. The "New Humans" from Lindia's city, believing Tsubaki responsible for Lindia's companions' deaths, repeatedly attack the shelter. Tsubaki, having exhausted peaceful options, decides to retaliate. He uses his advanced drone, "DRAN22," to destroy the city's "Amashiras" weather observation tower, issuing a final warning. The narrative concludes with Tsubaki reflecting on his changed life, now sharing his shelter with Suzuka, and the ongoing conflict with the "New Humans."
