An informant leads world-weary police detective Kim to small time crook Kang Tae-oh who says he murdered someone for hire 10 years ago. Before Kim can pursue the case, Kang is arrested for another crime. However he calls Kim from jail claiming he’s actually killed seven people. What follows is a psychological game of cat and mouse as the purported murderer tauntingly sends the agitated policeman on wild goose chases after unreported cases. Inspired by actual events, Kim Yoon-seok and Ju Ji-hoon’s riveting performances detail a fascinating police procedural that explores the dark side of human nature.