Lee Soo Yeon goes to a police station to confess having murdered her husband, Choi Joo Hyeok, a well-known entrepreneur. Soo Yeon's story is shocking: he treated his wife as a sexual plaything and even dared to covet her sister, Lee Ji Yeon. At the crime scene, he is indeed found stabbed to death and the investigation seems to be coming to an end. Despite the fact that the chief keeps telling him to wrap up the case, police officer Kang Gi Cheol continues to investigate. The whereabouts of Ji Yeon and the directors of the husband's company all seem strange. So, when news of Ji Yeon's suicide comes up and a recorded file of her will is found, the case becomes more and more complicated, and so does the relation between Gi Cheol and Soo Yeon.