Nagi operates as the barista within the Time of Eve café, an establishment enforcing a strict no-discrimination policy between humans and androids. She manages daily operations while discreetly ensuring patrons adhere to this principle of equality, often stepping in when customers attempt to determine others' biological status.

Her background identifies her as the human survivor of the Tokisaka Incident, an event eight years prior to the main story where she sustained injuries at age five during anti-android violence. She is Shiotsuki's daughter—the original creator of androids—and collaborates with him to establish the café as a sanctuary for human-android interaction. This space utilizes the "1138 override protocol," enabling androids to deactivate their identification halos and express autonomy, embodying Shiotsuki's effort to bridge societal divides. Despite monitoring by entities like the Ethics Committee and the APC, alongside the historical destruction of earlier café locations by anti-robot groups, Nagi persists in maintaining this refuge.

Her development focuses on fostering connections among patrons while concealing her traumatic past and familial ties. Post-credits scenes show her returning home and conversing with Shiotsuki, expressing optimism about the café's impact: she observes that his "children"—the androids—now coexist peacefully with humans inside the café and anticipates this harmony extending beyond its walls. This moment highlights her role in advancing her father's reconciliation vision and reflects her quiet commitment to societal change through the café's ongoing operation amid external scrutiny.