Alcia resides with her grandfather, Professor Grace, on Libertia, a planet terraformed using three giant orbital mirrors and once known as a "planet of death." She assists him in testing the Legaciam, a specialized heat-resistant relic armor prototype designed to function in extreme environments fatal to humans. This armor responds exclusively to Alcia, making her its sole pilot.

Her life shatters when Guild soldiers attack their home, seeking to capture Professor Grace and the Legaciam technology. Alcia barely escapes by piloting the Legaciam, initiating her flight from relentless Guild pursuit. This conflict forces her into a struggle to protect the Legaciam and rescue her abducted grandfather.

Alcia fights resiliently against Guild forces, utilizing the Legaciam's capabilities, including a specialized cutter weapon in combat. Her piloting role involves psychological strain during intense situations. Her relationships include allies like Dorothy, who provides support, and adversaries such as Zeno, Darts, and Blick, with whom she or her grandfather share unresolved personal histories. These interactions reveal fragments of her background.

The unresolved central conflict involves a mysterious tower in the desert that emits waves inducing psychological instability. This tower connects to Libertia's environmental fragility and the Legaciam's purpose.