Da Il and Sang Seob run a detective agency that is on the verge of going out of business. One day, a client comes to them, asking to find a missing child. However, the more Da Il digs, the stranger the case becomes.

Da Il suspects the teacher at the academy as the person who took the three kids. While working on the case at the office, he gets paid a visit by an aspiring detective. However, after a strange turn of events, Da Il meets a tragic end.

Yeo Wool thinks it's strange that Da Il disappeared from the crime scene, leaving the kids behind. The police investigating the case also finds the case strange. Meanwhile, Yeo Wool keeps looking for Da Il and worries that something might have happened to him.

Da Il comes to Yeo Wool's house and asks her about what she knows. From Yeo Wool's story, he learns more about the mysterious woman he saw. Together, they start looking for clues.

The manager of the restaurant Yi Rang used to work at jumps off a building after saying something ominous. Da Il can't help but feel sympathy toward Yeo Woo because he knows very well how she must be feeling right now. The woman in red is coming for them.

Da Il gets a feeling that Yi Rang's hearing aid will provide a clue to find out more about the woman in red. With Yeo Wool, he follows the lead. The woman in red's next target is the principal of the pre-school.