Read the full summary of the episodes here.
After the second video was launched with the riddle: 'What first walks on two legs, then on four legs, and finally on three legs?' the police manages to solve the riddle, but they don't know about the fact of their being two existing answers and jump on the first one they found. Shibazaki was also searching about the riddle and found out about the second answer of the riddle and also found the location of the bomb. He calls Kurahashi but seconds after the beginning of the call the bomb is set off and the Police Station destroyed. Kurahashi then suggested that Shibazaki comes back to work at the police as a detective in search for the people who are behind those terrorist attacks.Shibazaki transfares to his new division and it seems like some people don't like him. Kurohashi and Shibazaki meet each other in the park. The police has found one of the culprits behind the plutonium from the nuclear fuel reprocessing facility in Aomori. The culprit was a facility employee who had only worked there for a few months. His name was Yuzo Miyajima, but that was a fake name and they also got a sketch of culprit. Afterwards Shibazaki goes back to the police station to talk with a man who 'accidently' caused the black out in Tokyo. At the police station the man tells them he got an email saying if he cut the Kyuedogawa power line and made it look like an accident he would receive 2 million yen. While they were discussing the matter with other police officers, the third video of Sphinx came online. This time the riddle was: 'What's the building next to the house of the god who solved the riddle?'. This time they gave an exact time when the bomb would go off. Of course Shibazaki comes up with an answer. The next day Shibazaki shows up in a live video streaming where he unravels the answer to the riddle and afterwards threatens Sphinx saying they shouldn't mess around.
Before the next video of Sphinx is launched Shibazaki went to Aomori. There he tries to gather some more information about the culprit who worked at the plutonium factory. He doesn't get much information, because the culprit didn't talk much when he was working. When he gets back he goes out to eat at that time a new video of Sphinx is launched. The riddle is: 'At the place where the king who solved the riddle received a scary prophecy. Whose name would you carve on its entrance?' the riddle is related to Oedipus Rex and then state their hopes that their game would be played "without cheating", otherwise a hidden bomb will explode. Using the riddle, Shibazaki finds a website created by Nine and Twelve, which asks for a password related to three maxims inscribed at the temple at Delphi. Realizing that time is running out, the police decide to search an apartment building where Nine was recorded dropping off a suspicious package, although Shibazaki is still intent on solving the riddle. Police officers breach the apartment, only to find no bomb and a laptop instead. Time runs out, even though Shibazaki manages to solve the password (his surname) the timer won't stop and the bomb goes off. The reason the timer didn't stop was because the police cheated. Seconds later, police investigation reports of the attacks are leaked online.
Another video of Sphinx was placed with another riddle: 'Where did the punishment take place for FEZ 5889, the angel who planted a grapevine?', also saying that an explosion will occur after 8:00 p.m. if the riddle isn't solved before then. Using clues from the riddle, Shibazaki concludes the newest bomb is on the Shuto Shinjuku Line train. He then explains his discovery of a connection between all of the bombings: certain people connected to the bombsites participated in a seminar run by the Rising Peace Academy, a non-profit organization that promoted interaction between the Japanese government and the people. Later he hears the bomb won't be removed and goes to the chief to ask about it. The chief tells him it will be removed by a special assault team and they should wait for the orders, but the bomb didn't get removed. Shibazaki confronts the chief about the bombing, but he informs him he had no knowledge of it. While he asked who did this, Shibazaki realizes there was a girl with white hair sitting behind him.
During a comprehensive meeting, the chief announces the involvement of the Federal Bureau of Investigation in the investigation, surprising the other officers. After this meeting Kurahashi and Shibazaki meet outside and Kurahashi tells Shibazaki about his meeting with the FBI agents, which include Five, whose job is described as a researcher from an American organization called the Nuclear Emergency Support Team. Afterwards they get a message from sphinx which included a riddle that can only be decoded via Caesar cipher. Shibazaki solves it, but questions if this message is really send by Sphinx since it's too practical and it doesn't feel like there is an underlying message. The answer turns out to be a set of coordinates leading to Haneda Airport's International Terminal. The police try to respond to the scene, only to be told to stand by on orders from the superintendent general. Although Shibazaki goes anyway and sees his other colleagues joining him.At the airport, Shibazaki and the officers see messages being given to Nine and Twelve from Five in regards to the game and learn that the police ordered airport employees to transmit them. They realize that the latest Sphinx video was a fake created by the police, and that it is Sphinx they are communicating with. While they are still searching for the bomb Shibazaki get's a call from an unknown number. When he answers the phone a voice is heard and the one calling tells him he is Sphinx Number 1. He convinces him that the latest bomb isn't Sphinx's, and instructs him to infiltrate the control tower and take control of the autopilot system. Because a plane that is on autopilot is headed for a terminal filled with numerous commuters and the bomb is on that plane. Shibazaki agrees and enters the control room and forces one of the operators to divert the plane away from the terminal at gunpoint. The plane explodes without injuring anyone, and Shibazaki spots a masked Nine, who signals him in thanks before leaving.