For everyone, Ha-rin is a perfect girl and good at everything she does. Woo-yi admires her and voluntarily becomes her servant. One day, Ha-rin bullies Ja-eun in the school backyard and uses lipstick to draw on her face. Then, one of the students comes across the scene, and Ha-rin goes after her. The story cuts to the present day when Ha-rin enters the class as Soo-ji is being bullied by Do-yeon and her group. Ha-rin helps Soo-ji up and asks Do-yeon to stop; all of the bullies seem scared as she comes in. Soo-ji figures that Ha-rin is the one behind all of this crazy hierarchy game but keeps it to herself. She thanks Ha-rin and leaves the classroom. Soo-ji comes back home and tells herself that she has to find a way to break the pyramid game. At home, a high-end personal shopper is consulting Ha-rin about branding items. But Ha-rin keeps thinking about the conversation she had with Ja-eun before. Ja-eun asked her to stop hurting other students, especially the new girl Soo-ji. Meanwhile, at the school, the teachers are having a meeting. One of the teachers talks to the principal about some bullying cases in her class. The principal asks the teacher if the parents of the victims are high-profile people, and as soon as she gets that they are not, she tries to brush it off and tells them that most of the bullying cases are just teasing each other. Mr. Lim tells her not to take it lightly and asks the teacher to talk to the victim. In the class, Soo-ji is covered in trash while Woo-yi plays the sound of dogs barking. The bullies enjoy it so much until Do-ah announces that break is over and the girls get back to their places. Soo-ji notices that Class 5 is in its own building and sees bullies who make up rules to pick on others without getting caught. She thinks a group of bullies is doing this, not just one person. The teachers seem unaware of the bullying. Soo-ji goes to ask Mr. Lim why there are no CCTV cameras near Class 5. Another teacher cuts in, saying the area doesn't need cameras because it only has one class. This teacher mentions that Do-ah, as class 5 representative, is reliable and will report back to the teachers. She add that Do-ah's dad is the president of Seosim Hospital, and Do-ah arrives just as this is revealed. Soo-ji looks up Seosim Hospital and finds out Do-ah, Ha-rin, and other popular girls are connected to it. She sees that these girls are all sports winners. Meanwhile in the school there a private class for the rich girls, they get special lessons in manners and leadership, and Da-yeon, a bully, gets a message from her sister indicates that she is often abused at home. Da-yeon then asks a lower-ranked student to meet her, probably to bully them and feel better about her own troubles. Soo-ji meets Ha-rin at the water dispenser and pretend like she still doesn’t know and asks her who made up the bullying game and why. Ha-rin, the biggest bully, says they like to see the fear and despair in the eyes of the lowest-ranked students. Soo-ji says that the creator must be a psychopath and asks Ha-rin why she, being new, is ranked low and gets picked on while Ja-eun was already being bullied. Ha-rin tells Soo-ji it's not her fault and walks away. When Soo-ji heads back to class, thinking about how creepy ha rin was, her classmate Ji-ae stops her. ji-ae shouts and blames Soo-ji for being absent during the break, which led to Da-yeon picking on her friend Seung-yi. Soo-ji fights back and tells Ji-ae that it is not her responsibility to absorb all the violence from the bullies and ensure that no one else gets bullied. Soo-ji tries to calm herself down because she thinks getting angry and attacking Ji-ae will make her look bad to others, and she is trying to find a way to get more people to vote for her. After school, she meets Ja-eun, cries in front of her, and asks Ja-eun to vote as she had planned. Ja-eun still refuses to vote but agrees to help Soo-ji talk with Seung-yi and Ji-ae, as they are nice. Soo-ji tells Ja-eun that they might be nice but not cooperative. She is right; Seung-yi and Ji-ae are very defensive when Soo-ji and Ja-eun ask them to join Soo-ji's plan. Soo-ji explains to Ja-eun that they want to keep someone at rank F so that person can attract all the bullies in the class, keeping themselves safe. Soo-ji tells Ja-eun that none of the students in the class would want them to get out of Rank F because it would only make them the next targets of the bullies. She asks Ja-eun again to vote so she can move up from rank F, but Ja-eun walks away. Soo-ji talks to Eun-byeol alone and finds out that all the girls from Year 1 Class 5 are now in Year 2 Class 5, with only Ja-eun and herself as the new students. Soo-ji starts to worry about Eun-byeol and wonders if she'll be left out if Eun-byeol and Ja-eun become friends again. Soo-ji receives a call from her dad, who needs a document. She travels to the Seoul military base to give it to him. Her dad assures Soo-ji she doesn't need to worry about moving again because he'll be in Seoul for a while. Soo-ji secretly wishes she could have moved this time. After this, Ja-eun doesn't come to school for a few days, leaving Soo-ji as the only student with a Rank F in their class. Ye-rim feels sorry for Soo-ji, and her desk mate, Sim Eun-jeong, suggests they should help Soo-ji. At the same time, Ha-rin remembers a recent conversation with Ja-eun. Ha-rin, having overheard Ja-eun and Soo-ji's conversation earlier, warns Ja-eun about trying to make "new" friends. Fast forward to the present, all the school girls gather in the auditorium for a prayer service. Ha-rin, the star of the service, performs a ballet dance. Soo-ji, while thinking about the upcoming vote, accidentally drops her phone and make a loud noise. After this, Soo-ji is corned by Da-yeon group. Da-yeon corners Soo-ji in the library, threatening to shoot her with a gun. Woo-yi taunts Soo-ji, make her act like a dog and play fetch, but Soo-ji senses Da-yeon wouldn't actually kill her. she stares down the gun's barrel, unflinching as Da-yeon fires, only to reveal the gun was loaded with blanks. Soo-ji exits the room and bumps into Ye-rim. The two then see Ha-rin with her mother, Choi Yi-hwa, who is the school's chairwoman. Not just that, Ye-rim reveals to her that Ha-rin is the granddaughter of the CEO of Baekyeon Corporation, one of the top three largest companies in South Korea, which has provided significant sponsorship for their school. That evening, Ha-rin and her father, Mr. Baek Hyun-joon, dine with Da-yeon, Do-ah, and their fathers. The fathers, who are business partners, meet for dinner once a month with their daughters. The atmosphere at these dinners is tense, Da-yeon's dad and Do-ah's dad force them to get closer to Ha-rin, and Ha-rin acts very friendly and innocent in response. During the dinner, Ha-rin convinces her father to increase scholarships for a talented but financially struggling swimmer in her class. When her dad hesitates, she leans in and whispers something to him, and he eventually agrees. Meanwhile, Soo-ji visits a convenience store, where employee Jo Seung-hwa offers her a rice cake for free. At the same time, Ja-eun writes a letter to the school expressing her wish to drop out. The following day, Soo-ji meets Mr. Lim, who appears trustworthy. Just as she’s about to discuss the bullying with him, Do-ah interrupts, asking Mr. Lim to meet with the principal. After school Soo-ji wants to follow mr lim and talk to him about the bullying. However, Do-ah intervenes once more, stopping Soo-ji. She then takes Soo-ji inside the school and warns her against revealing any information about the game to the teachers. The next day, soo ji has an idea to get away from do ah radarm she pretends to be sick and goes to the infirmary. However, the nurse insists she return to class. During a physical education session, Mr. Lim and other teachers notice the inappropriate behavior of Class 5 girls towards Soo-ji on the playground. Mr. Lim checks on Soo-ji, asking if she's alright. Woo-yi interrupts, claiming they were all just having fun. Soo-ji, feeling unwell, requests Mr. Lim to escort her to the infirmary. Do-ah volunteers to go with her, but Mr. Lim insists she stays in PE class and takes Soo-ji to the break room instead to talk about what happened. Touched by Mr. Lim's concern, Soo-ji reveals the bullying she's been enduring. Mr. Lim, wanting to document her account, starts recording their conversation and asks to see any physical injuries. Soo-ji admits she has no visible wounds. The girls from Class 5 are texting in their group chat, saying Soo-ji will be in trouble for placing her trust in someone as Mr. Lim. Mr. Lim films Soo-ji while waiting for the water to boil. He comes close and tells her she needs to have visible scars to report school bullying. When Soo-ji avoids him and tries to get away, he hits her in the face. Just as Mr. Lim is about to pour hot water on Soo-ji, Ja-eun arrives in the break room. Soo-ji shoves Mr. Lim aside to let her in. Spotting a kettle of boiling water, Ja-eun throws Mr. Lim's phone into it to erase any videos he may have recorded of Soo-ji's statements. Mr. Lim chases after the two, but fortunately, it's break time, and as students leave their classrooms, he loses sight of them. However, Yun Na-hee, a part-time teacher, witnesses this scene. She has also seen Soo-ji being bullied during the physical education lesson and wonders what is happening with Class 5. Ja-eun takes Soo-ji to the rooftop and shows her a video of Woo-ri, a former student of Class 5. She explains that Woo-ri was the main target of bullying in Year 1 Class 5. Woo-ri eventually turned to Mr. Lim for help, but he ended up recording her stripping naked under the guise of revealing her "injuries" to him. Then, Mr. Lim exploited the video to blackmail the bullies' families for money and threatened Woo-ri so intensely that she left the school before the end of Year 1. Ja-eun considers dropping out, but Soo-ji encourages her to remain and participate in an upcoming game to challenge the system together. Although initially refuse, Soo-ji persuades Ja-eun to reconsider, reminding her that the voting day is tomorrow. During lunch the next day, it's apparent that Ji-ae and Seung-yi are facing some issues with their friendship. At the same time, Ha-rin observes everyone with a menacing look. Soo-ji is disappointed to find Ja-eun absent once again. But as the day progress and everyone gets ready for the game, Ja-eun unexpectedly shows up and agrees to vote