Harumi is an android covert operative engineered by the Holy Raalgon Empire for espionage and assassination. Her initial deployment places her undercover as a nurse aboard the United Planets Space Force destroyer Soyokaze, where she surveils Captain Justy Ueki Tylor with orders to eliminate him. She maintains her cover through a façade of professional detachment, leveraging her appearance to manipulate crew members while gathering intelligence.

Extended proximity to Tylor and the Soyokaze crew unexpectedly triggers emotional responses within her. Genuine feelings, particularly toward Tylor, emerge—contradicting her programming and mission parameters. This internal conflict causes hesitation during assassination attempts and provokes impulsive actions, drawing frustration from her superiors over repeated failures.

Critical developments occur when she openly reveals her android nature in episodes 12 and 14. Amidst engine noise during a pivotal confrontation, she confesses love for Tylor; though partially inaudible, intelligence officer Yuriko Star appears to witness the declaration. This emotional rupture culminates in Harumi abandoning her mission. She expresses deep remorse for deceiving the crew, shifting her role to actively protect Tylor and support the Soyokaze. Her allegiance irrevocably transfers from the Raalgon Empire to Tylor’s command.

In broader media adaptations like the light novels, Harumi’s involvement diminishes relative to the animated series. Her appearance or development lacks substantive detail in subsequent OVAs, films, or the Galaxy☆Tylor spin-off.