Ba Reum finally remembers what exactly happened to his family. He tries to set a trap to catch the mysterious OZ, and he finds out a secret about Dr. Daniel Lee in the process. Meanwhile, Moo Chi finds the unregistered car the OZ, the murderer who killed Chi Kook, used. 

Moo Chi finds out that Ba Reum was the killer and ferociously charges after him at the station. Moo Chi also suspects that Detective Lee is part of the OZ organization and tries to carry out an investigation on the two, but it's not easy. As flustered as he is, Ba Reum tries to remain calm to buy time until he figures out the killer of Chi Kook.