S1, E6: After tracking down Lee Taek Gyu with a secretly planted GPS device, Seo Jin is shocked when he confronts a dead body hanging from some bars. After the incident, Seo Jin continues to look for Kwak Song Ja, Ae Ri's mother, without realizing that he has already found her. Seo Jin later decides to keep his mouth shut, but instead, he informs Ae Ri about the time and place of her death. Meanwhile, Seo Jin gets surrounded by a group of policemen under the suspicion of Kwak Song Ja's murder.