Set in 1999, Choi Hyung-In (Yoo Jae-Myung) works as a detective. Ten years earlier, his wife died in a terrorist attack for which he blames himself and which he has never gotten over. One day, he investigates a murder case in a small town. He begins to suspect that the murder is somehow connected to the terrorists who took his wife’s life. About 10 years earlier, Jo Jung-Hyun’s (Han Ye-Ri) older brother took part in a terrorist attack. After that, her life fell apart, as she was labeled a family member of a terrorist. Despite everything, Jo Jung-Hyun was able to rebuild her life thanks to her niece, her older brother’s daughter. Her niece suddenly goes missing. Jo Kyung-Ho (Um Tae-Goo) is a mysterious prisoner, sentenced to life in prison. In 1989, he returned to South Korea after studying in Japan and released sarin gas at a train station in his hometown, carrying out the worst terrorist attack ever to occur in South Korea. Afterward, he turned himself in and was sentenced to life in prison. PROJECT ENTIRELY PRODUCED BY Jihwchi South Korea Drama