Nana, the director of the Nanase Detective Agency, is a detective skilled at professional pachinko. One day, a man named Fukushima, who is visually impaired, asks her to investigate his wife, Tomoko. She hardly ever stays at home, became addicted to pachinko, and even engaged in prostitution to make money. Around this time there is also a serial murder case involving regular pachinko players. Detective Omachi, who is investigating the case, asks Nana to cooperate.