In 1937, before World War II began, there was an organization called D Agency that trained spies. It was founded by Lieutenant Colonel Yuuki from the Japanese army. He believed in recruiting people outside of military academy graduates and personnel to become skilled agents in manipulation arts. These agents formed a specialized team for operations. One such agent, known as Jirou Gamou, embarked on a dangerous mission to obtain secret documents titled "Black Notes," while facing threats from both within and outside his own ranks.
Joker Game is an adaptation of the 2015 live-action film adaptation of Kouji Yanagis novel Joker Game.