Mother

Soo Jin is quite a cold-hearted woman who studies birds, which are her only interested. She doesn't like children, but she has to work as an elementary teacher for a few weeks. A girl named Hye Na in her class catches Soo Jin's attention, and she starts to worry about her because the child doesn't seem to be taken good care of by her family. Before Soo Jin quits the school, she goes to Hye Na's house to say goodbye, but she is terrified to see something shocking there.

Hye Na goes missing at a port, and her backpack and shoe are found near it. Soo Jin takes a bus with Hye Na to go somewhere else, and Seol Ak thinks he saw a girl that looks like Hye Na in the street. Soo Jin happens to stay in a guest house and tries to get a fake passport for Hye Na, but something goes wrong and Soo Jin feels frustrated. Meanwhile, Jae Beom keeps looking for Soo Jin as Young Sin asked, but he only finds out that she already left.

Chang Geun starts to interrogate Ja Young after going through the surveillance camera footage. Soo Jin and Hye Na go to an orphanage where Soo Jin used to live when she was a child, but they are taken aback when they get there. Hye Na keeps staring at Ja Young and cries when she is on TV, so Soo Jin tells her that she can go back to her mom if she wants to. The detective finds out that Hye Na liked birds and tries to reach Soo Jin.