The seemingly ordinary hardware manufacturing company is actually a cold-blooded killer company like copper metal. Chi Jung-dao (played by So Ji-sub) dresses in suits every day, yet he is a professional assassin with an impressive record for the company. He has worked for the company for ten years without a single failure, having honed a cold-blooded temperament and a ruthless heart that kills without flinching. However, upon encountering the new recruit, Roh Hyun (played by Kim Dong-wook), he suddenly sees his younger self. While undertaking a mission with Roh Hyun, Jung-dao experiences a moment of distraction. As he interacts with Roh Hyun’s family, he increasingly feels the warmth of family ties, and when he meets the woman he loves, Liu Mei-yan (played by Lee Myeong-yeon), his professional sensitivity starts to change. During one mission, his hesitation leads to failure, making him contemplate quitting for the first time; however, things are far from simple. In a single day, he transforms from the most promising employee in the company to the target being pursued by his former colleagues...
