Rinko Kashima is a teenage runaway and delinquent who encounters cyborg consultant Yamazaki Takurou early in the narrative. Her fugitive status manifests when Yamazaki shields her from police confrontation, initiating their partnership. Defying Yamazaki's preference for emotional distance, Rinko attaches herself as an observer and sidekick, accompanying him during his professional assignment at Itsusuba Electrics.

During this assignment, Rinko faces peril from another cyborg consultant, Suzuki. This encounter forces Yamazaki to reassess his rejection of human connections when his intervention to protect Rinko reveals an emerging sense of responsibility. Her presence actively undermines his intended isolation, becoming a catalyst for his development. The conflict with Suzuki highlights Rinko's vulnerability and the unforeseen repercussions of her alliance with Yamazaki.

Rinko’s background as a runaway and her role as witness to Yamazaki's consultancy inject a human perspective into the narrative’s technological and corporate focus. Her interactions primarily illuminate how human relationships impact Yamazaki’s cyborg existence, especially during crises necessitating his protection.