Natsumi Yukihira (Ryoko Shinohara) receives secret documents of an organization that controls the country from the shadows. Because of this, Natsumi's ex-husband, Kazuo Sato (Teruyuki Kagawa) pays a terrible price. Natsumi goes back to the Investigation #1 of Tokyo Metropolitan Police Department to take on the organization, but Natsumi becomes involved in a new case. She gets closer to the final enemy.