The 17th episode starts with Sung-Yeol’s dad telling Woo-Hyun to get out of his house so Seul-Bi, Woo-Hyun and Mrs. Ahn are leaving in Woo-Hyun’s house now. Mrs. Ahn looks around the house and finds some of Woo-Hyun’s baby clothes and pictures.
Sung-Yeol and his dad are alone at there house and his dad tells him whatever he wants he should not destroy himself to get it and Sung-Yeol tells him he has come to far to stop so just to think of him as already lost and his father protests this. Kwang-Shik teacher has come back and everyone is happy. He gives Joo-Ah the money from her boss at the convenient store that wasn’t treating her well. In class Sung-Yeol was drawing attention to Seul-Bi’s arm and then it started glowing and she hid it and Woo-Hyun threw a paper ball at Sung-Yeol to distract everybody.
While everyone was writing their tests the words disappeared on the paper and then they came back. Sunbae is out in the hallway watching this. When the papers are collected and brought forward Sunbae makes them disappear. Jae-Suk blames it on Seul-Bi because he has heard that she has magical powers and that she should get them back. Seul-Bi goes to the front and Sunbae makes them appear again.
At lunch Seul-Bi goes to sit with Ye-Na and she thinks Seul-Bi is making fun of her and she also saw the glowing so she tries to see her arm but she distracts her. Joo-Ah and Tae-Ho sit with them as well and Woo-Hyun makes her leave and Tae-Hoo follows her. He finds Seul-Bi alone to look at her arm and Joo-Ah pulls them apart and she tells him to distract him that she likes him and then runs away and he yells that today is their day one.
Seul-Bi paints Mrs. Ahn’s nails for her because she wants to be closer to her and Mrs. Ahn talks about how she doesn’t deserve to be a mother and Seul-Bi tries to reassure her. Seul-Bi then paints Woo-Hyun’s nails while he was napping. Later she comes and helps him take it off and then talks about how she wants to erase her shining spot and tries rubbing it too and cries. He tells her it is okay.
At school Mrs. Ahn cannot find the student’s test even though they were in a locked cabinet. A student overhears and then goes to class and gets everyone to pick on her and Sung-Yeol goes and grabs her and brings her away from everyone. Sung-Yeol and Woo-Hyun talk and he asks if someone is helping him and Woo-Hyun tells him that someone is trying to do what he is doing and Sung-Yeol tells him that he should give up on Seul-Bi so that the three of them can live here. Mrs. Ahn meets with her husband and she tells him that she can’t leave Woo-Hyun and Seul-Bi alone. He asks if she isn’t worried about Sung-Yeol and she tells him that she has to wait until they accept her. Woo-Hyun meets with Sung-Yeol and tells him to take care of Seul-Bi so that she won’t disappear forever and that he trusts Sung-Yeol because he also likes her and that he wants to stay with her.
Woo-Hyun tells Seul-Bi to believe him even if it sounds like a lie and that he wants her to go because she has become troublesome and he is sick of being in danger because of her. She hears he is lying and tells him that she will believe his lie. Sung-Yeol comes and picks her up to go to live with him and he walks in while she is unpacking and she is crying and he tells her not to cry in front of him again.
At school Seul-Bi overhears Mrs. Ahn talking about how she can’t find the tests and that it will look bad on their records. Seul-Bi goes running through the school and finds Sunbae in the gym and he makes the tests reappear but they are shredded and tells her he will do worse things to get her back in her place.
Ki-Soo sees Sung-Yeol ordering Seul-Bi around on the phone and confronts him about it and Jae-Suk comes up to him after and tells him he switched sides and starts beating him up but Tae-Ho and Byeong-Wook find them and stop the fight. They stand up to Jae-Suk and he gets scared and they leave. At the restaurant Joo-Ah finds the book about angels becoming humans and she asks if this is real and Woo-Hyun tells her that he is scared he won’t see Seul-Bi again and she tells him she will look for more books about how to stop it. Mrs. Ahn comes home and has questions about Seul-Bi and he won’t tell her anything and she thinks Seul-Bi will be looking for the tests and Woo-Hyun runs to find her. Seul-Bi is at the school taping together all the pieces of the test together and Woo-Hyun finds her. When she falls asleep he helps putting them together and she sees him doing it and then pretends to sleep more.
Woo-Hyun calls Sung-Yeol to come be with and he runs over and meets Woo-Hyun outside of the school. As they are standing there a whirlwind starts around them and Woo-Hyun yells at Sunbae and then they both run in opposite directions and gets out of it. Sung-Yeol goes to Seul-Bi and helps her continue taping the tests. Sung-Yeol at home is found by his dad crying and he tells his dad he is becoming a monster and to keep him under control and his dad tells him he will restrain him.
In the morning Seul-Bi brings Mrs. Ahn the taped tests and she asks questions about her and Sung-Yeol pulls her away and they don’t answer. Woo-Hyun at the restaurant is depressed without Seul-Bi. Seul-Bi is walking with Sung-Yeol and she gets a text from Ki-Soo saying Woo-Hyun is sick and that she should come and runs away. Sung-Yeol runs after her and stops her from going in and he pushes her away. She falls and faints, her wrist starts glowing weirdly.