Joker Game (Part 2) (ジョーカー・ゲーム（後編）) is the second episode of the first season of Joker Game. The episode continues from the cliffhanger of the first episode and has Sakuma investigate the incident behind John Gordon's house raid.
Having been unable to find evidence to prove John Gordon as a spy, Sakuma is left resorting to commit hara-kiri due to the bargain proposed by Miyoshi. As Sakuma kneels and pulls out his sword, he quickly starts processing all that Yuuki and the D-Agency told him on the nature of espionage. Sakuma remembers that spies remain invisible in plain sight. As Sakuma recounts this, he puts down his sword and says the evidence is behind the Imperial Portrait. Sakuma determines that the Imperial Portrait is the only place within the house that military policemen would not search, however, being that the D-Agency are only disguised as military policemen, searching behind the Imperial Portrait would not have been taboo. Sakuma deducts that Yuuki must have known about the prior raid on Gordon's house, hence sending D-Agency in mid-day to lower Gordon's guard. As Sakuma leaves Yuuki's office, he meets up with Miyoshi, who says he was impressed with Sakuma and that General Staff Offices will be "shocked" with his report.
Sakuma starts suspecting that Colonel Mutou must've sent the previous group of police to Gordon's house. However, being that the previous police raid found no evidence as to Gordon's position as a spy, Mutou, scared that his chances of promotion are in jeopardy, orders the D-Agency to search Gordon's house again, hoping they also fail to find evidence. Sakuma, however, still wonders as to how Yuuki has learned of the previous raid when Mutou kept his failure a secret. Sakuma remembers that on the day he received orders from Mutou, he clearly was hungover. Sakuma determines he might have been to a classy restaurant or inn.
Sakuma reports to Mutou that the evidence was behind the Imperial Portrait. Astonished, Mutou asks if they took the evidence, Sakuma says the D-Agency only confirmed the existence of the evidence (microfilm, as it is revealed), much to Mutou's anger. Sakuma says that Gordon is currently under Yuuki's watch, who plans to use him as an asset, and that the microfilm containing photos of communication codes would be useless if the army change their encryptions. As Mutou is angrily shouting at Sakuma, Sakuma hands Mutou a cigarette case and asks if it was his, Mutou says yes, to which Sakuma replied that he found the case on the floor of the Hanabishi inn.
Prior to reporting to Mutou, Sakuma conducts a private investigation at the Hanabishi. Questioning a hostess of the inn, it is confirmed that Mutou was there on the night of the first raid. Sakuma asks if there were any other people that night, and the hostess says that there was a man, the president of a small trading company, that drank too much and fell asleep. Sakuma asks if this man had any distinct traits, specifically if the man had a lame left leg and wears a white glove on his right hand, however, the hostess nods no. However, the hostess remembers the man picking up a cigarette case left on the floor of Mutou's room and turning it into the hostess. The hostess asks for Sakuma to return the cigarette case to headquarters.
Upon discovering about Mutou's conduct, Sakuma tells Mutou that it is illegal to reveal the details of a police operation. As Sakuma leaves, Mutou begins wrecking his office in anger.
Sakuma meets up with Yuuki, and Sakuma reveals that his use of a cane is a disguise, as well as is his wearing of a white glove on his right hand, and that his left hand is actually prosthetic. Sakuma deducts this as while Yuuki was at the inn, he had his hand wrapped around a geisha's waist, and thus picked up the cigarette case with his left hand. Sakuma had a expert of forensics from Army Imperial College to examine the cigarette, which had fingerprints from Sakuma, the hostess, and Colonel Mutou. Yuuki comments that Mutou was careless and revealed the information of the raid while drunk, and with Mutou with no choice to cooperate with D-Agency, Yuuki plans to use Mutou to drag more funding into D-Agency. Impressed, Yuuki offers Sakuma to train with D-Agency.