Hanegi Manami is a typical Japanese middle school student living an ordinary life, despite her grandfather's work creating unusual mechanical inventions. She follows a routine of attending school and interacting with classmates. This normal existence shatters when an antagonistic robot attacks her school, specifically threatening her friends and damaging her lunch. This event forces her involvement with experimental technology.

She rapidly becomes the operator of the specialized powered armor suit Del Power X, built by her grandfather for her capabilities. Her transition into a mecha pilot stems from familial ties and urgent need, not prior training or ambition. Her motivation arises from protective instincts towards her peers and personal anger over her ruined lunch, not broader heroic goals.

The narrative shows limited character evolution beyond this fundamental shift into a defensive role. Her actions focus on confronting immediate threats to restore normalcy. Family dynamics highlight her relationship with her inventor grandfather, who enables her mechanized combat role. Interactions with a senior schoolmate involve shared transportation to school, indicating routine social connections before the conflict.

During the OVA's events, her operational experience with Del Power X remains singular, focused solely on resolving the school attack. The storyline does not explore her background, personal history, or future development beyond this incident. Relationships are defined by circumstantial reactions to external conflicts, lacking deep interpersonal exploration or growth arcs.