On the eve of World War II, an international Asian city becomes a hub of a high-stakes “spy game” as spies from countries such as Japan, the UK, the Soviet Union, and Germany compete to give their respective countries any possible advantage in world diplomacy.
Kato (Kamenashi Kazuya) is about to receive a severe punishment for disobeying his superiors when he’s scouted by a man named Colonel Yuuki (Iseya Yusuke) to become a spy for the secret intelligence agency D Kikan. He endures rigorous training and is eventually given his first mission as a secret agent. Kato must infiltrate the multicultural city referred to “Devil’s Metropolis” in order to take a critical “black notebook” from U.S. Ambassador Graham.
Kato attempts to find the notebook along with a mysterious woman named Rin (Fukuda Kyoko). Meanwhile, D Kikan gets caught up in a fierce rivalry with a radical faction of the Imperial Japanese Army.