북한의 남파특수공작 5446 부대. 20000:1의 경쟁률을 뚫은 최고 엘리트 요원 원류환, 공화국 최고위층 간부의 아들이자 류환 못지 않은 실력자 리해랑, 공화국 사상 최연소 남파간첩 리해진. 세 사람은 5446 부대의 전설 같은 존재이다. 하지만 조국통일이라는 원대한 사명을 안고 남파된 그들이 맡은 임무는 어처구니 없게도 달동네 바보, 가수지망생, 고등학생이다. 전달되는 명령도 없이 시간은 흘러만 가고 남한 최하층 달동네 사람들과 부대끼며 살아가는 일상에 익숙해져 간다. 그러던 어느 날 그들에게 전혀 뜻밖의 은밀하고 위대한 임무가 내려진다.
The story is about two Korean National Police University students, Ki-joon (Park Seo-joon) and Hee-yeol (Kang Ha-neul), who witness a kidnapping and track it down. However, the authorities are busy with the kidnapping of a son of a business mogul. They decide to embark on their own amateur investigation, which gets them into all sorts of trouble.
A rock climber tries to save the day when a mysterious white gas envelopes an entire district in Seoul, South Korea.
Woo-jin, a furniture designer who wakes up in a different body every day, falls for Yi-soo, a woman he meets through his work.
Kim Jae-hyun (Yoo Yeon-seok) is a sports manager and former talented basketball player. His only wish is to send a novice and promising player Kang Chul to America. To fulfill his wish, he must head to Busan to find and convince Kang Chul. Meanwhile, Bae Soo-jung (Moon Chae-won) works in an advertising agency and must also travel to Busan for a business trip. The two meet on the Korea Train Express and spend 24 hours in the unfamiliar city of Busan, South Korea.
Instead of calling her boyfriend, Yoon-jung accidentally calls a total stranger, Hyun-seung, a man who is having trouble getting over his ex-girlfriend. She ends up having phone sex with him and later, they become comfortable with each other and start talking about their respective relationship problems. They eventually decide to meet and a more intimate friendship develops, which leads to both falling for each other.
A honest cop seeks justice for a common man against all odds. A rich boy seeks revenge on the cop.
Jong-Woo (Shin Ha-kyun) went to prison four times for petty crimes likes burglary and car theft, but he now works as an auto mechanic. He has a 17-year-old son named Gi-Hyuk (Lee Min-ho (actor born 1993)), which he raises by himself. Gi-Hyuk is a smart kid, but troubled. The father and the son also do not get along. Although, Jong-Woo might appear like an irresponsible father, he tries his best and even works at night as a private taxi service.