The film cuts between three separate stories.
The first is of young George. An overweight boy who is bullied by his peers and neglected at home. He projects the abuse he receives at school back onto his younger brother Charlie. George is an avid collector of mod and rocker records. He tries to befriend the bully, Alex, at school by enticing him to look at his record collection in which Alex seems interested. Alex is also a tormented child from an abusive background. George decides to take his father's record collection in to school to show Alex for which he is ridiculed. Alex proceeds to smash all of the records. George's father has left home and the records are the only memory George has so he vows to get revenge.
A lonely chef with a speech impediment takes a job as a professional killer in order to raise the money he needs for an operation on his tongue. Known as "Killar", he and his partner "Ballet" make a rule to only kill rude and impolite people. After killing each one of his victims, "Killar" goes to the same bar where he meets "Her", a woman who becomes attracted to him. His life begins to unravel after he and "Ballet" kill the wrong person by mistake.
Jin-sook has a close relationship with her son, Don-woo, and is surprised when he announces his engagement to Su-jin. After the wedding, the three end up living together, with a nervous Su-jin keen to impress her new mother-in-law. But Jin-sook is determined to sabotage her son's marriage.
The film starts by showing the city streets of K-Town in New York, then goes straight into one of the most common places in Korean Culture. A Room salon (RS) where Korean Mobster Jin Ho Chun (Jun-ho Jeong) is running the place as a money launderer for the Korean mafia. As Chun is making his usual errands, such as making sure the Room salon is running smoothly and greeting customers. Chun goes and checks on the VIP members, where also his mistress Sook Hee (Jane Kim) is at. Chun then grabs the bag full of cash and makes his way into his car. While Chun's driving off, another car blocks his way and he gets shot to death in the back.
Yoo Ji-yeon is a Korean university graduate who is stuck working as a waiter under the name "Jenny Yoo" in a Macanese bar after her colleague stole her credit card and all of her money before running away, forcing her to pay her increasingly rising debt. Her Macanese friend offers her a job interview with Kim Sung-yeol, the illegitimate son of Kim Seok-gu, a successful gambling corporation chairman who owns half of the casinos in Macau. Sung-yeol asks Ji-yeon to become Seok-gu's new bride, so she can inherit his property and divide it for the two of them. Sung-yeol is unable to inherit his property due to his status.
Tae Gun-ho (Jung Jae-young) is the best collection agent in his firm, admired by his colleagues and dreaded by those he visits. He’s known for gathering his debts by any means necessary, and keeps a cattle prod handy while on the job. Following a series of unexpected fainting spells, Tae is told by a doctor that he has liver cancer, and would need a transplant to have any chance of surviving beyond three months. And so he puts his professional skills to work, setting out to collect a different sort of debt by tracking down the recipients of organs donated by his late son. First among his sources for a liver is Cha Ha-yeon (Jeon Do-yeon), a beguiling fraudster with a long list of enemies.
The North and South Korean governments are on the verge of reopening the Kyungui Railroad, which connects the two Koreas, as a further step toward reunification. Japan refuses to accept the decision, claiming rights to the railway lines based on official documents imprinted with the imperial seal of Emperor Gojong of Joseon a century ago. Yet an age old conspiracy is uncovered where the imperial seal with which Emperor Gojong signed the documents is suspected to be fake. It is a race against time and hidden agendas as the South Korean president (Ahn Sung-ki) employs the outspoken historian Choi Min-jae (Cho Jae-hyun) and the descendant of the Joseon royal bloodline Kim Yu-shik (Kang Shin-il) to find the authentic seal and prevent the history of Japanese occupation from repeating itself. In the meantime, Japanese economic sanctions divide the South Korean government, and its armed forces appear on the border of South Korea threatening its sovereignty. Eventually, the authentic royal seal is found and Japan apologizes for its occupation.