Mage Bilstein, daughter of Rebuild engineer Nathan Bilstein and linked to associate Derrida Yvain, inherits a legacy shaped by her father’s work on autonomous DZ machines. During her eighth birthday, Derrida gifts her a critical software patch access key designed to rectify a flaw in the DZs’ programming—a gesture that inadvertently ties her to the technology’s looming repercussions. When Nathan and Derrida’s warnings about the DZs’ dangers are dismissed by their superiors, Nathan is assassinated by Hans Andrei, their superior, forcing Derrida into cryostasis with a vow to protect Mage.

A decade later, Derrida emerges into a war-ravaged world and learns from Mage’s childhood friend, Yuri Dietrich, that she is presumed dead. Yet visions haunt him: a girl named Ange, bearing Mage’s likeness, hints at unresolved threads in her fate. These apparitions intertwine with Mage’s past experimentation with time-leaping technology, which once left her collapsed, implying deeper entanglement in temporal anomalies central to the conflict.

Though physically absent, Mage’s influence propels Derrida’s quest to honor his promise, her uncertain fate echoing the story’s themes of fractured legacies and the weight of unkept vows.