Lee Yong Gu is a mentally impaired father with the intellect of a six-year-old, who lives in a run-down house along with his daughter of the same age, Ye Seung. One day, he gets into a physical altercation with the police commissioner, who has just purchased the last Sailor Moon backpack for his daughter, a gift Yong Gu was saving up to buy for Ye Seung. Soon after, the police commissioner's daughter dies in a freak accident while she is taking Yong Gu to another store that sells the same backpack. When he tries to resuscitate her, a woman witnesses him and mistakes him to be molesting her. Yong Gu is falsely accused of the abduction, murder, and rape of a minor. The police quickly take advantage of his disability and force him to admit to committing the crimes, while ignoring exonerating evidence. Yong Gu is imprisoned and assigned to Cell No. 7, the harshest cell in a maximum security prison.
As Korea's biggest crime organization 'Goldmoon' expands its powers, Kang (Min-sik Choi), the head of police investigation planning department, orders the undercover cop Ja-Seoung (Lee Jeong-jae) to participate in project "New World", that will take down 'Goldmoon'. Ja-seong must choose either to follow Kang's orders as a cop or to keep his loyalty with Jeong Cheong (Jeong-min Hwang), the under boss of the 'Goldmoon' crime organization
Kang In-Ho (Gong Yoo) is a newly appointed teacher at a school for the hearing-impaired in Mujin city. On the way to his new job he becomes involved in a minor car accident and takes his car to a local car repair shop. There his already wrecked car is bumped by a woman named Yoo-Jin (Jung Yu-Mi). Yoo-Jin is an employee at the Mujin Human Rights Center. On the first day at his new school, In-Ho meets the school's principal and director of administration. They are an identical twins. The director of administration asks for a bribe of 50 million WON ($50,000 USD) to work at their school. In-Ho's financial situation is already in dire circumstances. His daughter who is staying with his mother suffers from asthma. In-Ho's wife has passed away. In-Ho makes a phone call to his mother asking for the money. She delivers the 50 million WON by taking out the deposit money for their home. While teaching the hearing-impaired students, In-Ho feels something strange about the kid's distant appearances. On his way home, In-Ho notices one of his students Yoo-Ri sitting on the ledge of her dorm room window, which is several stories above ground. He rushes into the dorm building and makes it into Yoo-Ri's room to pull her away from the window. Yoo-Ri then leads In-Ho to a door down the hall and stops. In-Ho goes into the room and sees the superintendent of the dormitory beating a male student named Yeon-Doo. In-Ho is shocked by the brutality and eventually takes Yeon-Doo to the hospital. In-Ho also makes a phone call to Yoo-Jin, the lady from the huma rights center who bumped into him earlier, and asks her to come to the hospital. Soon, In-Ho and Yoo-Jin uncover unfathomable actions committed by the school's faculty against the students. Their work to break the children's silence is only beginning. Meanwhile, In-Ho feels his own pressures to stay silent as his new job already cost his family their home's deposit money and medical bills are piling up for his daughter.
Kyung Chul is a dangerous psychopath who kills for pleasure. He has committed infernal serial murders in diabolic ways that one cannot even imagine and his victims range from young women to even children. The police have chased him for a long time but were unable to catch him.
One day, Joo Yeon, daughter of a retired police chief, becomes his prey and is found dead in a horrific state. Her fiance Soo Hyun, a top-secret agent, decides to track down the murderer himself. He promises himself that he will do everything in his power to take bloody vengeance against the killer, even if it means that he must become a monster himself to get this monstrous and inhumane killer.
Ex-detective pimp Jeong Ho is angry because his girls keep disappearing without clearing their debts. One night, he gets a call from a customer and sends Mi Jin. But when Mi Jin meets the customer, Jeong Ho realizes the phone number of the customer matches that of the calls the missing girls got last. As something smells fishy, he searches for her. During his search, Jeong Ho dents a car in the alley. When Jeong Ho spots blood splattered on the driver’s shirt, he senses the man, Young Min, is the suspect. After an intense chase, Jeong Ho finally catches Young Min. But because of Jeong Ho’s pretense as a cop, they are both taken to the police station. At the station, he bluntly tells the policemen that he has killed the missing women, and the last girl, Mi Jin, may still be alive. As the police force is obsessed with a random search for corpses, Jeong Ho is the only one who believes Mi Jin is still alive. With only 12 hours left to detain the serial killer without a warrant, Jeong Ho’s hunt begins.
A group of Korean archeologists find a skeleton and identify it as Lee Jin-Seok. But Lee Jin-Seok is still alive and he is now an old man. It is his brother Jin-Tae who went missing in the Korean War. We travel from the present to 1950, when the Korean War started. Jin-Seok and Jin-Tae, Jin-Seok?s brother, are young men who suddenly find themselves catapulted into a bloody world so different from their quiet, rural lives. As the war progresses, the war begins to poison Jin-Tae?s mind. Jin-Seok is lost when he finds that he no longer knows who his brother is.
The lonely and silent rider Tae-suk breaks in empty houses and lives a normal life while the owners are traveling. He does not steal anything and moves from house to house without any loss other than food, and he cleans the houses, provides small repairs or washes some clothes to pay for the hospitality. When he enters in the house of Sun-hwa, he does not see the woman that is wounded in her room after being beaten up on by her abusive husband Min-gyu Lee. Tae-suk helps the hurt woman and when Min-gyu returns, he hits the husband with golf balls and Sun-hwa leaves her husband with Tae-suk on his motorcycle. When they break in the house of an old man, they find that the man is dead and Tae-suk provides funeral service for him. However, his son returns and Tae-suk and Sun-hwa are arrested by two abusive police detectives. He is sent to prison and Sun-hwa is forced to return home. But she never forgets him.