About Gon is a hitman, abandoned by his mother shortly after immigrating to America. Wracked by guilt for accidentally killing an innocent young girl, the situation becomes even thornier when his boss assigns him the job of killing her mother. Gon's new target, Mo-gyeong, a risk manager at an investment firm, has buried herself in work in her grief, and is completely unaware of her role at the heart of a dangerous conspiracy. Then, she meets a man who wants to tell her the truth behind the death of her child. (C) CJ Entertainment