As Products has been acting suspiciously, Dae-sung and Myung-sook tail her to see if she is the killer. However, Products is not the only suspicious one. Although it is clear that Yool is being abused by her father, she denies help. Dae-sung tries to think why Yool is denying help and confidently says that Dae-sung is not the murderer. This allows him to come up with another lead. (thetvdb.com)