The story of a huge incident faced by Seo Soo-yeon from the support management team that supports and manages NIS field agents in China, Jang Cheon-woo, a hidden NIS black agent and Do Jin-sook, deputy director of overseas parts.

A Korean-style spy investigation show with a story about a top National Intelligence Service (NIS) agent. In his endeavor to uncover the internal traitor that brought him to his downfall, he confronts a much bigger enemy behind the organization. Han Ji Hyuk is the top field agent in the NIS. He is held in awe by his colleagues for his perfect record and skill at completing missions. He had been driving an organized crime syndicate into a corner when he vanished off the face of the earth, but he returns a year later to shake up the syndicate once more. Seo Soo Yeon is the head of team 4 of the Crime Information Center who is excellent at performing her duties and solving cases. She has great affection for people, and she especially cares for her teammates.

Son Ji Eun moves to a small city due to her husband's new job as a civil servant. She works part-time at a mart. Son Ji Eun is quiet and sincere. Her life in the small city becomes boring. Son Ji Eun's life is shaken by Yoon Jung Woo. Yoon Jung Woo is a biology teacher at a local school.

Two apathetic police academy recruits who become best buddies through the tough training together witness a woman being abducted right before their very eyes. As they were taught in the academy, they quickly report the incident to the police, but the police are in no hurry to jump on the case. So the duo decide to take the matter into their own hands and rescue the woman.

To pay a debt, a married man (Kwon Sang-Woo) receives billions of won from a woman. In return for the money, the man gives himself to the woman.

Three shots are fired and the president of South Korea suddenly goes missing from his vacation villa. Three Days is a condensed-time thriller that follows the struggles of elite Blue House bodyguard Han Tae Kyung to find and protect the president. With the aid of local police officer Yoon Bo Won and fellow Blue House guards, will Han Tae Kyung be able to save the president before it’s too late?