Hiromi Ishizaki is a central figure in the community of Third Street, primarily defined by her complex and often troubled relationship with the aspiring writer Ryunosuke Chagawa. She is a woman of a somewhat mysterious past who works at a local tavern, a setting that establishes her as part of the neighborhood's working-class social fabric. Chagawa harbors a deep, unspoken love for her, and his primary motivation as a writer is to achieve the success he believes is necessary to win her heart and build a family with her.

Her role in the story is catalyzed by a significant act of trust. She asks Chagawa, who lives across the street from her, to look after a young boy named Junnosuke, who has nowhere else to go. Although Chagawa is reluctant at first, his devotion to Hiromi compels him to agree, and the boy comes to live with him. This decision sets in motion the film's central dramatic tension, as Hiromi subsequently distances herself from the pair.

Personality-wise, Hiromi is portrayed as a forlorn and perhaps conflicted individual. While she trusts Chagawa with the child, she misinterprets his intense work schedule and focus on his writing as a lack of interest in her. Feeling neglected because he never visits her at the tavern, she embarks on a secret career as an exotic dancer, using the stage name Betty Asaoka. This new path, which is a significant departure from her life on Third Street, brings her into contact with undesirable admirers and further complicates her circumstances. Her life becomes one of abrupt changes and hidden struggles, contrasting with the more stable, grounded lives of the other residents. Her sudden disappearance from the neighborhood is a key event that deeply affects Chagawa and Junnosuke. Hiromi does not possess any special abilities in the traditional sense; her strengths are emotional rather than physical, defined by her capacity for caretaking in leaving Junnosuke with Chagawa, and her vulnerability as she navigates a difficult path toward what she perceives as personal success. Her development is seen in her transformation from a bargirl to a stage dancer, a move that isolates her from the supportive community she once relied on.