Ga-min is passionate about studying and puts all his efforts into it. However, he never received a good grade, which made him go to Yusung Technical High School. The school is known as a gangster training school, and unlike Ga-min, not many students are into studying. However, Ga-min wants to try a new method of studying, which is forming a study group. He asks his classmate Se-hyun to join him, but he tells Ga-min about a problem he has.

Ga-min gets into an unexpected fight against Hyeon-u, a school bully. As the fight goes on, the two become the center of attention of everyone in school. At that moment, a man enters the classroom that has become a mess because of the two, and it turns out that he is a school inspector. The vice-principal who got furious about the incident decides to expel Ga-min from school.

Someone applied to the study group. Ga-min is excited to meet the applicant, but it turns out that it is Ji-woo, Hyeon-u’s twin sister. Kyu-jin, a member of the student council, picks on Ji-woo, and Ga-min confronts him. Han-wul tells Hyeon-u about Kyu-jin who was blackmailing Ji-woo. Meanwhile, Ranked 1 among the 1st years comes to see Ga-min.

Jun is impressed by Ga-min who defeated the rankers. He applies to join the study group and asks Ga-min to teach him how to fight. However, Ga-min rejects him because he only wants students who actually want to study in the study group. Jun decides to join the gang to become stronger, but it only gets him in trouble. Ga-min and his friends go to rescue him.

The study group is finally complete. But the school’s top student, Kim Ho-min bullies Se-hyun, who grew up in the same neighborhood. He tramples on Se-hyun’s pride and beats him up, calling him a poor loser. Ga-min steps up to help him, but it only makes Se-hyun feel like a real loser. After refusing to go to Ga-min’s house, Se-hyun wanders around alone and ends up running into Ho-min alone.

Ga-min breaks the curfew that he promised because of Se-hyun, and his mom tries to transfer him to another school. Han-kyeong and the study group, who can’t give up on Ga-min, persistently chase after Ga-min’s mom and try to persuade her. But that’s when the reserves of the Yeonbaek Gang barge in after finding out about Han-kyeong’s plan about Pi Han-wul.

Ga-min runs into Pi Han-wul’s bodyguard, Kim Sun-chul, at the hospital where his mother is hospitalized. In fact, Sun-chul was working for Pi Han-wul because he needed to take care of his sick grandfather. In order to pay his grandfather’s hospital bills, Kim Sun-chul decides to go to prison on the false charge of murder instead of Yeonbaek Gang. Ga-min finds it out and steps forward to help Sun-chul with his friends.

The Study Group sneaks into the Reserves General Meeting and struggles against the Yeonbaek Gang. And Pi Han-wul forces Kim Sun-chul to make a false confession to Detective Na Tae-man. Meanwhile, the fated midterm exam finally begins. The Study Group must improve their grades and climb up at least ten places to hold a disciplinary committee against Pi Han-wul. Will they all succeed?

The Student Council Committee will summon Han-wul, and Han-wul’s past is revealed. Han-wul comes up with a scheme to stop the committee. He makes fake news and puts it online to make it go viral. Because of this, the study group members are falsely accused of being a school gang. Han-kyeong must make a choice to protect her students.

The study group members learn about the incident Han-wul was involved in a year ago and why he is so obsessed with the school gang. Since this might put Han-kyeong in danger, the members try to come up with a solution to get through this crisis. Meanwhile, Han-kyeong tries to persuade the Vice Principal to stand with her, but she gets in danger instead.