The President has ordered Young Ki Eun's arrest. But when he turns up dead, the President orders Sa Woo and Baek San's arrests. Meanwhile, Hyun-Jun, Seon-Hwa, and Cheol-Yeong try to locate the nuclear bomb before it goes off at 5pm.
Kim Hyun-Jun asks for Park Cheol-Yeong's help in getting his revenge on the NSS for abandoning him. Cheol-Yeong will only agree if Hyun-Jun helps to plan an assassination attempt on a North Korean traitor.
Park Sang-Hyeon and Seung-Hee are beginning to suspect Sa-Woo and Baek San of being traitors. Park Cheol-Yeong is starting to have second thoughts about the nuclear attack. Meanwhile, Hyun-Jun informs the South Korean President about IRIS.
Hyun-Jun makes contact with the secret man that saved his life in Hungary, in order to find out more about IRIS and his parents. Seong-Hee has become obsessed, once again, with finding Hyun-Jun, which is getting her in trouble with the NSS.
A mysterious man has been trying to track down Hyun-Jun because of a USB drive that he received from the late Hong Seung Ryong. It turns out that the USB has information on a mysterious terrorist organization, called IRIS.
Hyun-Jun finally discovers that Seung-Hee is still alive. He escapes, with the terrorists, from NSS with a piece to a nuclear weapon. Now Hyun-Jun has gained Park Cheol-Yeong's trust.