Kim Hyun Joon is an assassin who belongs to a top secret organization known as the "NSS" whereas T.O.P is an assassin who works in another secret organization located in the United States called "IRIS" and was ordered to kill Hyun Joon. Seung Hee is a psychological analyst who plays an important role in bring Hyun Joon into the "NSS." Jin Sa Woo is Hyun Joon's enemy and falls in love with Seung Hee as well.
This drama focuses on the life of Jung Yak Yong, a gifted scholar from Joseon who also had a keen eye for investigation.
When three young girls from the same orphanage turn up dead, weathered detective Kim (Park Yong-woo) realizes he has a serial murder case in his hands. One of the suspects on his list is Ryu Jung-ho (Kim Sang-kyeong), a troubled photographer who has the mysterious ability to read minds. Having just returned to Korea from the US, Jung-ho becomes the guardian to a young girl, Su-yeon (Han Bo-bae), whose mother is in a coma. Is Jung-ho protecting the girl, or is she the next potential victim? As Kim digs deeper into the case, the situation reaches a crisis point when Su-yeon goes missing.
A community is driven into a state of tension and paranoia as more and more children mysteriously go missing. In the midst of this, Ji Soo and Hyun Soo's daughter, Soo Ah, is also kidnapped. A special kidnapping rescue squad is dispatched to investigate the case, attempting to find out where the children disappeared to and whether or not they're still alive.
One sunny day, a young boy named Jo Kang meets a curious young girl, dressed in a bright yellow raincoat. Jo Kang instantly becomes friends with Ari, and falls instantly in love with the beautiful but rather strange young girl - only for her to one day disappear!
The story jumps to ten years later, and Jo Kang is now in high school. One day, completely out of the blue, Ari contacts him and asks to meet again. Although they have not seen each other in a decade, they have a wonderful time together, and the love between them begins to grow once more. But then, Ari disappears once more, leaving Jo Kang devastated.
Can Jo Kang track down his true love? Will he ever discover why Ari keeps disappearing? Will he be able to do anything about it?
Kang-jae grew up under a jobless, gangster father. When Kang-jae accidentally meets Lee Dae-hae (Suh In-sok) and his son Sun-mo, he feels more attached to Dae-hae than to his own father. Through Dae-hae and Sun-mo, Kang-jae learns the basics of magic as well as what fatherly love really means. Sun-mo, on the other hand, has a love-hate relationship with his father, who only cares about magic and nothing else. Meanwhile, Sun-mo is heartbroken by Dan-young, who falls in love with Kang-jae. Before that Dan-young was living with Sun-mo, mistakenly thinking that he is her long-lost brother before she was adopted. Yun-jin, Dan-young’s stepsister, instantly falls in love with Kang-jae and Kang-jae decides to marry her, not for love but for the sake of fulfilling his own ambitions at the price of spurning Dan-young.