Nagisa Kashiwagi, a student at Shuchiin Academy, leads the Volunteer Club. She belongs to the school's VIPs, stemming from her prominent family background as the daughter of a major shipbuilding company's chairman and the granddaughter of the Japan Federation of Economic Organizations' director. Academically, she excels, consistently achieving high examination rankings.

Her relationship with Tsubasa Tanuma, son of a hospital director, began after he approached her, following student council president Miyuki Shirogane's "wall-down" romantic advice. This relationship encounters challenges, including an incident where Nagisa suspects Tsubasa of infidelity with their classmate and fellow Volunteer Club member, Maki Shijo. Confronting him reveals Maki was merely assisting Tsubasa in selecting a gift for Nagisa, resolving the misunderstanding.

Nagisa frequently interacts with Kaguya Shinomiya, seeking and exchanging relationship advice. She approaches Kaguya due to Kaguya's perceived lack of prior romantic experience, while Kaguya similarly consults Nagisa, creating a mutual advisory dynamic. This facilitates discussions about romance among peers.

While exhibiting moments of vulnerability, such as jealousy during the incident with Tsubasa and Maki, she maintains a generally friendly aura at school. Her influential family background and connections secure her position within Shuchiin Academy's elite circles.