Park Mu-jin (Ji Jin-hee) is the South Korean Minister of Environment, with little ambition as a politician. After a diplomatic incident involving free trade negotiations with the United States, President Yang Jin-ma (Kim Kap-soo) dismisses him from the office.
The next day, as the President announces to the National Assembly that he is making peace with North Korea, the building explodes, killing all of the South Korean line of succession. Park Mu-jin, whose resignation had yet to become effective, survived the accident. He is sworn in as Acting President for 60 days, and starts uncovering the truth behind the bombing.
Lee Joon-hyuk as Oh Yeong-seok, former ROK Navy Lieutenant Commander and independent member of the National Assembly. He is the show's counterpart of Congressman Peter MacLeish.
Huh Joon-ho as Han Joo-seung, Chief Presidential Secretary later as Presidential Policy Advisor. He is arrested at the end of the series for conspiration on the bombing. He is the show's counterpart of Charles Langdon.
Kang Han-na as Han Na-kyung, NIS Terrorism Task Force Analyst. She is the show's counterpart to Hannah Wells.
Bae Jong-ok as Yoon Chan-kyung, leader of the opposition Seonjin Republican Party. She is the show's counterpart of Kimble Hookstratten.
Supporting
Park Mu-jin's Family
Kim Gyu-ri as Choi Kang-yeon, First Lady of South Korea, Park Mu-jin's wife and a human rights lawyer. She is the show's counterpart of Alex Kirkman.
Nam Woo-hyun as Park Si-wan, Park Mu-jin's teenage son. He is the show's counterpart of Leo Kirkman.
Ok Ye-rin as Park Si-jin, Park Mu-jin's daughter. She is the show's counterpart of Penny Kirkman.
The Blue House
Son Suk-ku as Cha Young-jin, Presidential Office Senior Administrator and appointed as Chief Presidential Secretary after Han Joo-seung resignation. He is the show's counterpart of Aaron Shore.
Choi Yoon-young as Jung Soo-jung, secretary of Park Mu-jin. She is the show's counterpart of Emily Rhodes.
Lee Moo-saeng as Kim Nam-wook, Presidential Office Administrator and later Acting Press Secretary, former defector from North Korea. He is the show's counterpart of Seth Wright.
Lee Do-yeop as An Se-young, Chief of Civil Affairs.
Baek Hyun-joo as Min Hee-kyung, Presidential Secretary.
Park Keun-rok [ko] as Park Soo-kyo, Presidential Office Administrator.
Park Choong-seon [ko] as Ko Young-mok, Director of the National Security Office.
Song Yoo-hyun as Kim Eun-joo, administrator of the second subdivision office.[6]
National Intelligence Service
Kim Joo-hun as Jung Han-mo, NIS Terrorism Task Force Chief. He is the show's counterpart of Jason Atwood.
Jeon Sung-woo as Seo Ji-won, NIS Terrorism Task Force Cyber Specialist. He is the show's counterpart of Chuck Russink.
Kim Jin-geun [ko] as Ji Yoon-bae, NIS Deputy Director. He is the show's counterpart of John Forstell.
Lee Ha-yool as Kim Jun-oh, NIS agent. He is the show's counterpart and a composite of Senator Scott Wheeler and Gabriel Thompson.
Republic of Korea Army
Choi Jae-sung as General Lee Gwan-mook, Chairman of Joint Chiefs of Staff and Chief Director of the Joint Defense Headquarters. He is the show's counterpart of General Harris Cochrane.
Ahn Nae-sang as Kang Sang-goo, former three term Mayor of Seoul. He is the show's counterpart to and a composite of Governor James Royce and former president Cornelius Moss.
In the table above, the blue numbers represent the lowest ratings and the red numbers represent the highest ratings.
This drama aired on a cable channel/pay TV which normally has a relatively smaller audience compared to free-to-air TV/public broadcasters (KBS, SBS, MBC and EBS).