In an era trembling on the edge of an AI revolution, Towasa Oumagi stands out as a prodigy. Her adopted brother, Akira Himegami, is one of the few who understands the heart behind her code and stands unwaveringly by her side against the prejudice she often faces as an AI pioneer. During a shareholders meeting meant to unveil a breakthrough that could reshape humanity, chaos erupts when a shooter guns down Towasa and Akira in rejection of their ideals.
With the attack being his last memory, Akira opens his eyes, only to realize centuries have passed. He finds himself in a deserted laboratory among a city in ruins, with no idea what became of Towasa or the world. A father and daughter find him and take him into their modest home, where he is shocked to discover that civilization has regressed. His peaceful days are shattered when he is captured by OWEL, a global organization that now governs the world and controls access to knowledge from the old era. When his captors decide to execute him, a mysterious figure appears and lays waste to the entire squadron with her terrifying inhuman abilities. After rescuing him, she introduces herself as Yuugure—an android—and asks Akira to marry her. If things were not already unbelievable, Yuugure's face is a perfect reflection of Towasa's.