Episode 5 of "Study Group" kicks off with Pi Han-ui and his loyal companion, Min-hwan, besting Kang Dong-su's gang, who had let them down. It becomes evident that Pi Han-ui harbors ambitions to usurp his father and seize control of the family enterprise in the near future.
Meanwhile, in Seoul, the study group is engaged in a meeting with the cream of the crop from Manil High School. A mishap occurs when Ji-woo inadvertently texts Ga-min the incorrect address, sending him to the adjacent Manik High School instead. Meanwhile, the students from Manil confess that they are being tormented by their neighboring school's bullies, expressing anxiety over Jun-min's tardiness, fearing he is enduring abuse at their hands.
Their fears prove justified as Jun-min is indeed enduring a brutal beating at the hands of the Manik bullies. By the time Se-hyeon and Ji-woo rectify their mistake and inform Ga-min of the correct location, he has already confronted the bullies at Manik, defeating them soundly and rescuing Jun-min. Despite a rocky beginning, the students eventually settle down to their studies and enjoy a productive session. As they bid farewell, Jun-min expresses contrition and gratitude to Ga-min.
It transpires that Jun-min was once a classmate of Ga-min's at his former school, where he excelled academically and had been part of a study group that excluded Ga-min. Reflecting on his past behavior, Jun-min regrets his meanness towards Ga-min and urges him to persist. His heartfelt encouragement brings Ga-min to tears. Elsewhere, Han-gyeong informs Wu-Yeol, Manil's teacher, of her decision to remain at Yusung Technical High School due to an unfulfilled mission.
The following day, the study group returns to Yusung Technical High to their astonishment: the principal has assigned them a dilapidated, grimy room for their club. However, Ga-min's infectious enthusiasm galvanizes them into cleaning it up and transforming it into a presentable space. Once their task is complete, Ho-min, another bully, appears to taunt and provoke the study group. Fortunately, they remain unperturbed and refuse to rise to his bait.
Concurrently, Han-gyeong meets with the Deputy Principal, proposing a meeting with the disciplinary committee to discuss disciplinary action against Pi Han-ui. Unsurprisingly, the Deputy Principal opposes the idea, challenging Han-gyeong to raise the study group's grades by ten points if she wishes him to risk confrontation with Pi Han-ui. Han-gyeong accepts the wager, with Lee Joon eavesdropping on their conversation.
After her meeting with the Deputy Principal, Han-gyeong convenes the study group and unveils their placement rankings, revealing no shocking revelations except for Ga-min's position as the second-to-last in the school. Despite this, Ga-min remains steadfast in his determination to climb up the ranks. As they make their way home later, Lee Joon shares with the group the details of Han-gyeong's conversation with the Deputy Principal, casting a palpable sense of pressure over them all. Suddenly, Se-hyeon receives a message that alters his demeanor entirely; he excuses himself hastily, claiming he has a meeting to attend.
It transpires that his father has summoned him to the construction site immediately after school, a testament to his father's enduring reluctance towards his studies. A flashback unfolds, depicting a younger Se-hyeon excitedly rushing home to share his exam success with his parents. Upon arrival, he finds them engaged in a heated argument, with the neighbors eavesdropping outside. His father, furious that his mother had taken out a loan, faces the wrath of debtors hot on their trail.
On his way to the site, Se-hyeon encounters Hee-won, and a conversation blossoms, where she praises his resilience. As they stroll along, they unexpectedly bump into Ho-min and his gang of bullies. The bullies once again resort to violence, targeting both Se-hyeon and Hee-won. At this critical juncture, Ga-min arrives on the scene and courageously stands up for his friends. However, Se-hyeon is deeply troubled by his inability to defend himself and feels reliant on Ga-min's assistance once more.
With a heavy heart, Se-hyeon returns home to find his furious father awaiting him, ready to unleash another beating. This time, however, Se-hyeon confronts his father and walks out with defiance in his heart. To his surprise, Ga-min is waiting for him outside. Ga-min generously offers his home as a refuge, but Se-hyeon politely declines. He explains to Ga-min that, although he is deeply grateful, he yearns to win a fight on his own. He feels utterly helpless and hates the perception of his own weakness.
Ga-min reflects on Se-hyeon's words as he takes a taxi back home. That night, while out for a stroll, Se-hyeon serendipitously crosses paths with Ho-min once again. Fortunately, Ga-min has a change of heart and calls Se-hyeon when he spots Ho-min approaching. Through the phone, Ga-min coaches Se-hyeon on how to evade punches. Unfortunately, Ga-min's phone conks out midway through the fight, leaving Se-hyeon to confront Ho-min alone. To everyone's astonishment, Se-hyeon manages to knock Ho-min unconscious without Ga-min's direct assistance, marking a significant turning point in his journey.
