Sayaka Kanzaki hails from a privileged upbringing until her parents' abrupt disappearance upends her life. Forced to find work for survival yet uncertain how to begin, she possesses waist-length red hair, striking purple eyes, and a youthful teenage demeanor. As an honor student, she excels academically and shares a romantic relationship with a classmate.

Financial desperation leads her to accept part-time employment at a family restaurant. Its owner, Kuroki, reveals her parents vanished following a business collapse that incurred massive debts. He then delivers an ultimatum: join the restaurant’s covert midnight shift—where waitresses provide sexual favors to patrons—to accelerate debt repayment.

Though horrified and resistant, Sayaka consents to the night work. She views it as the only path to amass enough money, clear her family’s obligations, and possibly ensure her parents’ wellbeing.