Tachibana was admired by those around her for her intelligence, but in truth, she derived satisfaction from bullying her classmates. When she discovered that her classmate's mother, Yui, was a beautiful, big-breasted woman, her attitude changed completely, and she began acting unusually friendly toward her. Unaware of this shift, Yui remained oblivious to the fact that her own mother was being targeted. Tachibana stared intently at Yui's voluptuous breasts as if appraising them, drawing her in closer and closer.