It is the year 2050. A young engineer named Derrida Yvain gains fame for his role in developing the "Autonomous Machine DZ" at Rebuild, a manufacturing firm established by his father. One day, Derrida and his colleague Nathan uncover a defect in the DZs and attempt to alert their superior, but their warnings are dismissed. Even though Derrida and Nathan recognize the threat, they reluctantly choose to delay action and attend Nathan's daughter Mage's birthday party instead. The following day, after a peaceful morning, Derrida and Nathan are suddenly assaulted by unidentified forces. During their escape, Derrida enters a cold sleep pod, and ten years later, he awakens to a war-torn, devastated world. As Derrida is attacked by a swarm of rogue DZs, he nearly surrenders, but remembers Nathan's final words. "Take care of Mage." Despite the grim fate that has befallen him, Derrida sets out to find Mage.