Soo Ji's suspicion was right; Ye Won led Ja Eun into Harin's trap that she had set for her. However, Soo Ji arrived in time and interrupted them. It turns out they made a deal: Ye Won will inform Harim if Soo Ji and Ja Eun do anything that annoys her, and they noticed the duo kept questioning and following Ye Won. Harim called out Soo Ji's plan but told her it would fail anyway. However, Soo Ji still managed to stop Harim from bullying Ja Eun. It seems like something had happened between them, given how mean Harim was to Ja Eun and how defenseless Ja Eun was against her. Ji Ae panics when she finds out that Harim knows about their secret plan. Soo Ji thinks Harim doesn't know everything and they should still go ahead with their plan. Ms. Yoon talks to Mr. Lim and asks him to arrange a meeting with a counselor for the girls of class 5. But he doesn't care and ignores her. Ji Ae is picked on by Da Yeon's group and hides in the bathroom. Her former best friend seung yi follows her and tries to make her tell about Soo Ji and their plan. Then, Seung Yi goes to see Harim. Seung Hwa sees the pyramid game on Soo Ji's phone and remembers something important. It turns out he is the brother of Woo Ri, the girl who was bullied in the first year and had to leave school. He is also a computer expert. In class, Soo Ji starts to understand the secret relationship between Yerim and Eun Jeong when Woo Ri asks Eun Jeong about the lipstick she's wearing, since she usually doesn't wear makeup. Soo Ji realizes they are secretly dating and Yerim has been helping her. Also in class, Woo Yi starts to pick on Shin Ye but Hae Jun stops her, saying it's too much. Ji Ae is taken away to be bullied by Da Yeon's group. Ja Eun wants to help her, but Soo Ji stops her. This makes ja eun remember a bit of her past in the orphanage, when she was little and playing with another kid. Da Yeon invites Harim to her house for dinner at her dad's request. However, Harim notices Da Yeon getting closer to Seol Ha, which annoys her, so she declines the invitation. This refusal leads to Da Yeon being beaten by her dad at home. Do Ah and her dad discuss this at his hospital, where it's revealed that Da Yeon was beaten because she failed to maintain a good relationship with Harim which could have helped her dad make better connections with the Baekyeon company. Do Ah's dad also reminds her to keep a good relationship with Harim to protect their hospital and her future. At school, Soo Ji finds out a secret about Hae Jun: she didn't vote for anyone she hangs out with. So, Soo Ji texts her to meet up. Meanwhile, Ms. Yoon finds Ji Ae crying in the bathroom and asks Soo Ji what's happening in their class because she can't see any signs of bullying. However, Soo Ji is still upset by what Mr. Lim did, and remembers her dad always telling her to handle her own problems. So, she just thanks the teacher and leaves. Later, Soo Ji and Ja Eun meet with Hae Jun. Soo Ji believes Hae Jun doesn't vote for her friends because she doesn't want them to outshine her, although outwardly she acts like a protective and loyal friend. Soo Ji threatens to tell Hae Jun's friends that she didn't vote for them, and Hae Jun agrees to vote for Soo Ji's group to keep them quiet.

That night, Ji Soo and Ja Eun walk home and see Seung Hwa heading in the direction of the school. Seung Hwa breaks into Classroom 5 at night to do something. Soo Ji catches him red-handed. Ja Eun also remembers that he is the brother of Woo Ri. Woo Ri is still traumatized by her memories of the school and can't leave her room. Meanwhile, Soo Ji realizes Seung hwa is a notorious genius hacker who won a prize in an international cybersecurity contest. He is here for the pyramid game and also because of his sister, Woo Ri. Later, Soo Ji tells ja eun they should involve him in their plan because he's a genius hacker and can help them better than what Yewon can do. The next day, she meets him at the convenience store and invites him to join them so he can understand what happened with his sister, and he agrees.

He starts by hacking into Jae Hyung's phone and sees that he has a lot of pictures of Eun Jeong and is quite a pervert. He informs Soo Ji the next day, and she discusses with Ja Eun how to use this information to blackmail Jae Hyung to vote for them. However, Ja Eun proposes to do the task herself. She decides not to use the pictures to threaten Jae Hyung but tries to befriend her instead, and she finally succeeds. So now they have two more people to vote for them. The last girl whom Soo Ji wants to convince was supported by Harim; she helped her win an art contest, and Soo Ji wants to change the target to someone else.

However, Soo Ji still finds it difficult to completely trust Ji Ae and Ja Eun. At night, Soo Ji asks Seung Hwa to find information about Seung Yi, and she finally knows her weak spot. She texts Seung Yi and threatens to expose her secret. The next day, one day before the monthly voting, the principal invites all the parents of Class 5 students for a meeting. They are led to a different room. Soo Ji's dad surprisingly shows up, but no one is friendly with him. Ms. Yoon comes in and asks him if he's aware of the school bullying going on in Soo Ji's class, shocking everyone in the room, including the principal, who comes in with Harim's mom and Mr. Lim.

Meanwhile, Soo Ji meets up with Ye Rim and reveals that she already knew Ye Rim's secret and also the reason why she still participated in the game despite hating it. It is because Harim knew about the secret relationship between Ye Rim and Eun Jeong and used it to force her to join in the game. Soo Ji goes on to ask Ye Rim to be ranked as an F student this time. She wants to see if someone perfect like Ye Rim, who is pretty, famous, and comes from a rich family, will get bullied or not, and that will contribute to bringing Harin down.