"Nora Joshikōsei" centers on the life of Ririka, a high school girl who leads a double life. By day, she is a diligent and well-behaved student, but by night, she transforms into a rebellious delinquent, roaming the streets and engaging in fights. This duality stems from her desire to escape the pressures of her strict upbringing and societal expectations. Ririka’s contrasting personas create tension as she struggles to reconcile her true self with the image she presents to others.

The narrative explores Ririka’s interactions with her classmates, particularly her growing friendship with Yuka, a cheerful and outgoing girl who becomes curious about Ririka’s hidden side. Yuka’s persistence gradually breaks down Ririka’s walls, leading to moments of vulnerability and self-discovery. Meanwhile, Ririka’s nighttime activities draw the attention of rival delinquents and local gangs, escalating conflicts that threaten to spill into her school life.

As the story progresses, Ririka’s dual existence becomes increasingly difficult to maintain. Her involvement in street fights and her attempts to protect Yuka from the dangers of her other life force her to confront the consequences of her actions. The series delves into themes of identity, loyalty, and the struggle to balance personal freedom with societal expectations. Through its exploration of Ririka’s journey, "Nora Joshikōsei" presents a nuanced portrayal of adolescence, rebellion, and the search for authenticity.