In 1782, King Jeong-jo of Joseon asks detective K to investigate a series of murders related to a case of corruption within the government.

A Korean-American secret agent from USA sneaks into Korea. He tries to make money by selling a high-priced painting. However, he is soon chased by the ones unwilling to expose it, and meets a woman who wants the painting.

Returning to the island where their mother lives alone, four siblings discover that the elderly woman suffers from dementia.

A desperate 35 year-old Young-sil is more than ready for full time job. And finally she gets a call from National security department as an intern. But her joy lasts no long, soon asked to leave. Accidently she discovers a secret about her boss and she suggest a deal of full time job to help him; secret spy.

Young-Hoon works for his mother’s restaurant, but he prefers hanging out with his friends. He then meets Yeun-ah, a tough lady that works in a room salon as a barmaid. She takes the initiative by coming to his restaurant, when he is working, and propositions him in a playful way. They become a couple, but their relationship is always volatile. They fight constantly (physically and verbally), but the next moment kiss and make up. Meanwhile, Young-Hoon already has another girlfriend, who is his finance!

Set in a teahouse in Myeong-dong, Seoul right after the end of the Korean War, The 12th Suspect follows the suffocating psychological showdown that takes place between a detective and the 11 suspects who find themselves caught up in a murder case.

When a series of murders occur in Kanghwa Island, Detective K and his partner are once again called upon to solve the case. Along the way, he teams up with a beautiful woman with amnesia and together they discover Vampire bite marks on all the bodies. As they investigate further, they realize that the woman is somehow closely connected to the deaths.

Cheol-woo, a Korean law student at Waseda University in Tokyo, secretly leads a student reading club that doubles as an independence movement. He falls in love with Yumiko, daughter of Miike, a Japanese official behind colonial policies, and struggles with their forbidden romance.