Nana Takenouchi is a high school student and photographer living in Japan. She possesses a natural ability as a spirit medium, which causes her to unconsciously attract supernatural entities. Her father was a ghost photographer who lost his reputation, and after his death his spirit continued to haunt her, creating a strained relationship with his memory. Nana is initially timid and uneasy about her abilities, fleeing when the magical law enforcer Toru Muhyo identifies her as a medium. Over time she becomes more curious and determined, frequently seeking out Muhyo and his assistant Jiro Roji Kusano to help with spirit-related incidents. Her motivation stems from a desire to understand her father's legacy and come to terms with her own connection to the supernatural world. Nana serves as a recurring client and occasional ally, providing photographic evidence of ghostly phenomena that ordinary people cannot see. She develops friendships with the teenager Kenji Sato, who introduces her to the bureau, and with Roji and Muhyo, often accompanying them on investigations. Her medium abilities make her vulnerable to possession and infection, as seen when she accidentally spreads a contagious spirit during Roji's promotion exam at the Magical Law Association. Through these experiences, Nana grows from a frightened girl into a more confident participant in supernatural matters, using her photography and sensitivity to assist in resolving cases.