The 13th episode starts with Woo-Hun finding out that he is Mrs. Ahn’s son. She tries to explain why she couldn’t tell him and he tells her that he has no parents and to leave so he can say goodbye to his grandmother.
He said goodbye and cried. Woo-Hyun figures out that Sung-Yeol knew and that was why he was acting weird. They meet and Woo-Hyun says he doesn’t care and nothing is changed but Sung-Yeol says it matters to him. Woo-Hyun tells him that he doesn’t care and that he doesn’t want a mother and that Sung-Yeol can have her. Sung-Yeol tells him that he is just as pretentious as his mother.
Mrs. Ahn is sick at home in bed and Sung-Yeol’s dad asks him to take care of her because he has to work. Woo-Hyun throws his necklace away. Jae-Suk is talking to his gang and they are in trouble because they didn’t answer his call. A girl from class sees them and tells them the teacher wants to see him so the tall guy and Jae-Suk leave. The shorter gang member helps the girl pick up the tomatoes she dropped and she tells him he doesn’t need to see the teacher.
Jae-Suk talks to Sung-Yeol and tells he should be thankful because he could be alone with Seul-Bi and piss Woo-Hyun off, Woo-hyun overhears and gets mad thinking that Sung-Yeol had planned the lock in with Jae-Suk. Ye-Na tells a girl from class that she wants to have a birthday party and that she is not inviting Young-Eun.
Seul-Bi is cleaning the garbages and finds Woo-Hyun’s necklace that he threw out and takes it out of the trash. Woo-Hyun meets Sung-Yeol’s dad and he asks if something happened between them because Sung-Yeol seems depressed but Woo-Hyun doesn’t say anything.
Seul-Bi goes to see Sung-Yeol and tells him that it was neither of their faults and he gets mad and tells her not to talk about Woo-Hyun in front of them and he is going to steal everything away from him including her.
Mrs. Ahn goes to the shop and talks to Woo-Hyun and tries to give him money but he doesn’t want it and they both agree she needs to be Sung-Yeol’s mother now. She goes outside the shop and cries and Jae-Suk sees her.
Woo-Hyun makes food for the Ye-Na’s party and when he is cooking with Seul-Bi he sees her arm shining so he sneakily tells her to keep her arm covered. When everyone comes he realizes it is Ye-Na’s party and tries to refuse but can’t. Ye-Na makes an excuse that all the bathrooms are full and wants to use the upstairs one and Seul-Bi agrees and she snoops around.
Woo-Hyun gets called out by Sung-Yeol’s dad and meets them and Woo-Hyun explains that he met his mother and that they are going to live separate lives.
Seul-Bi waits up for Woo-Hyun listening to him singing. They talk about what family means and that they are people who are forever on their side forever and she tells him that she is on his side and they promise that she will be on his side later and forever.
Sung-Yeol’s dad goes home and explains to Mrs. Ahn that Woo-Hyun’s mother is not going to be apart of his life and that he would not even be able to eat if his son had to pay his father’s debt and that he feels so sad. Sung-Yeol talks to Mrs. Ahn later alone and she asks why he didn’t tell his dad and he tells her he wants to watch her sink slowly. He tells her that he should be the one to reveal it to his dad.
Ye-Na tells the gym teacher that Seul-Bi is living with Woo-Hyun. Ye-Na and the girls approach Seul-Bi and make her feel bad about living with Woo-Hyun.
The teachers have a meeting and the head human angel has become the new head of the board and is running the meeting. He asks if there is any legal reasons they can’t live together and there isn’t. The teacher argue it will wreck the school reputation. The nurse says that she doesn’t like how the adults are pushing adult values on them and taking away their innocence. He tells them to make a proposal or accept their love. He also reminds them to find the teacher that left and to find him and not be so cruel by not even checking in on him.
The gym teacher talks with Mrs. Ahn and decides he wants to find Woo-Hyun’s mother. During Mrs. Ahn’s lecture Sung-Yeol asks since they are talking about family values he asks what she thinks of a mother that abandons his son and raises some other kid and she tells him to visit her during office hours. After school Woo-Hyun goes to talk to Sung-Yeol about his childish behavior and Sung-Yeol acts like a brat. Sung-Yeol hits Woo-Hyun and since he promised grandmother and Seul-Bi not to fight he tells him to keep hitting him.
Woo-Hyun tells him that he wants Sung-Yeol as his friend and in his future and no matter what he does he will not hate him. Seul-Bi and Mrs. Ahn both find them and they pull them apart. Woo-Hyun tells her to only about Sung-Yeol and to throw everything away. Sung-Yeol gets on the railing and tells Woo-Hyun to get on too because he is curious who Mrs. Ahn would save first. Seul-Bi tries to get to him but her Sunbae moves things in her way so she can’t get to him. She tries using her powers and Sung-Yeol notices and Woo-Hyun gets to her and stops her. Mrs. Ahn pulls Sung-Yeol down from the railing and this ends the 13th episode.