Asami Yuki is a 17-year-old Tokyo high school student holding a part-time convenience store job. She sports ochre-dyed blonde hair, a change from her natural black, and has brown eyes. Her tanned skin and frequent use of gal-specific language reflect gyaru subculture influences, though she switches to standard Japanese when serious or angry. Despite her rebellious appearance, she excels academically.

Coming from a wealthy family of lawyers, Asami experiences parental neglect. This strained relationship fueled her gyaru transformation as an attempt to gain their attention. At their shared workplace, she becomes Sayu Ogiwara's first peer friend in Tokyo. Asami quickly perceives Sayu's tendency to hide behind a "plastic smile," using her emotional perceptiveness to see through others' falsehoods. During a significant outing, Asami shares her own family struggles with Sayu at a meaningful location, helping Sayu feel accepted and establishing mutual trust.

Her observational skills prove critical when she notices a vehicle following Sayu, leading to the discovery that Sayu's brother has located her. Asami is later present when Sayu explains running away: her friend Yuuko committed suicide due to bullying, and Sayu's mother blamed her for the tragedy. Asami provides ongoing support as Sayu navigates her return to Hokkaido and maintains contact afterward.

Following Sayu's departure, Asami continues pursuing her aspiration to become a novelist, a career path conflicting with her family's expectations.