A race to capture a North Korean nuclear physicist leads to the detention of Agent Kwon. Lee Jung Woo receives an overseas assignment from NTS with a new partner.

Lee Jung-woo and the NTS try to hunt down a Russian mob boss who has come to Korea to kidnap Dr. Kim Myung Guk.

Lee Jung-woo and Kim Ki-Soo are partnered up to track down a terrorist in Europe and who or what his next target is.

Kwon heads the NTS team over to Italy to rescue the president's daughter. Son Hyuk receives a special visit from a researcher in Japan.

NTS and DIS continue their mission to rescue Soo Young. Hye In applies for a new job, while Jae Hee meets with her estranged father.

A guard catches Hye In hacking the computer system. Kwon suspects NTS has a mole and assigns both Jung Woo and Jae Hee to investigate.

Jung Woo continues to question Hye In, but is given a new assignment as a bodyguard. Asian popstar BoA guest stars.

Jung Woo continues to protect BoA. Kwon sends reinforcements to help Jung Woo, Jae Hee, and Joon Ho extract the SNC.

Jung Woo and Hye In's kidnappers want the SNC. Jung Woo agrees to do whatever it takes to save Hye In, as the SIC continues to hunt for the moles.

Despite having betrayed his country, Kwon still believes in Jung Woo and allows him to follow his suspicions about Dr. Kim's last message.

Having been found out as being part of Athena, the DIS and NIS hunt down Son Hyuk. Ki Soo tries to decode Dr. Kim's final message.

Jung Woo, Jae Hee, and Joon Ho form an investigative team to uncover Son Hyuk's past and history with Athena.

A guilty Hye In reevaluates whether she wants to continue being an Athena agent. Jae Hee discovers the shocking truth about her father.

Unable to let go of Hye In, Son Hyuk keeps her guarded in his safe house while setting in motion his largest attack against the South Korean government.

Jung Woo faces off with Son Hyuk and his men. Jae Hee arrests Hye In for treason.

Son Hyuk takes drastic measures to get Hye In back, as Jung Woo must find additional help to stop him.

Hye In feels guilty about Sung Chul's death and actively helps NTS bring down Athena. The North Korean government plots to eliminate all former agents, including Kim Sun Hwa.

With Son Hyuk becoming increasingly unstable, Athena decides to replace him with another member to lead the organization in another terrorist attack.

Son Hyuk warns Hye In to get out of Seoul, spurring the NTS to find Son Hyuk before he launches his nuclear missile.

With the death of another integral member of NTS, Jung Woo and Son Hyuk have their final showdown.