So Yoon is trying to convince Ga Young's mother about Ga Young's Fabry disease. Hyung Kil gives Woo Jae a task to find a walnut tree in order to catch the serial killer. Yoo Na is hospitalized by her mother.

The investigators are getting closer to the serial killer and set out a bait on the internet. So Yoon comes closer to finding out the biological father of Hye Jin.

Officer Han and Woo Jae are breaking into Pil Sung's house to find a nearly killed So Yoon. Pil Sung runs away and tells So Yoon about the father in which she slowly starts to connect the pieces.