Twenty years have passed since the failure of Project Elysion, a massive workforce automation project. Artemis, the artificial intelligence at the core of the project, had chosen to attack humanity, and Earth has been devastated ever since. A girl named Empress wakes up in the base of an underground research facility, having lost all memory of her past. She meets a young brother and sister duo named Norito and Miya, who came to the base to collect precious water. Empress aims to reach the surface together with the two of them, but she comes face-to-face with many different enemies, and…