Episode 5 of *One High School Heroes* picks up right where we left off, with Ui-Gyeom and Yoon-ki squaring off against Nam-yeop. Yoon-ki and Ui-Gyeom take turns confronting Nam-yeop, their words and actions escalating until they force him to his knees in a humiliating apology to the student he had been bullying. While Yoon-ki demands the apology, Ui-Gyeom discreetly captures the moment on video. They issue a stern warning to Nam-yeop, threatening to release the footage online if he ever dares to bully another student again.
After the confrontation, Yoon-ki and Ui-Gyeom unwind together, sharing drinks and a moment of camaraderie. Later, they change clothes, and Ui-Gyeom heads off to his cram classes. Meanwhile, Yoon-ki pays a visit to the boy in the hospital. He plays the video for the unconscious victim, informing him that he made Nam-yeop kneel in submission. With a determined glint in his eye, Yoon-ki vows to make all the remaining bullies kneel as well. As he leaves the room, the boy's fingers twitch slightly, a silent sign of awareness.
The next day at school, Yoon-ki informs Ui-Gyeom that they have identified their next target and plan to confront him the following day. Meanwhile, Hong-II and Jin-woo attempt to coax Seung-joon back into their gang. However, their efforts are thwarted when Ui-Gyeom and Yoon-ki intervene.
Ui-Gyeom is pleased to see that Seung-joon has resumed his boxing training. Seung-joon confides in them, revealing that the school bullies, including Ji-hyuk, Seung-ki, Sung-wook, and others, weren't always so arrogant. But once they discovered the power wielded by their fists, it went to their heads. With a hint of accusation in his voice, Seung-joon tells Ui-Gyeom that he, too, has become arrogant, just like Seung-ki and the rest.
A new student, Lee Geol-jae, arrives at the school and is placed in Seung-ki's class. Unbeknownst to him, he takes Seung-ki's seat, sparking an immediate confrontation. However, Geol-jae exudes an even more domineering aura, and his fighting skills are unparalleled. He doesn't retaliate but deftly dodges Seung-ki's attacks with expert precision. The teacher arrives just in time to halt the escalating clash.
Later, Seung-ki hatches a plan to pit Ui-Gyeom against Geol-jae. He sends Hong-II to goad them into a fight. Hong-II approaches Ui-Gyeom and Yoon-ki, spinning a tale that Geol-jae is attempting to take over the school. Unfazed but intrigued, Ui-Gyeom and Yoon-ki head straight to Geol-jae's class, ready to face him head-on.
Geol-jae, desperate to avoid conflict, leads the rowdy group to the rooftop for a peaceful discussion. However, Ui-Gyeom, fueled by a fiery temper, is itching for a brawl. Just as tempers flare, Yoon-ki steps in, recognizing Geol-jae's formidable fighting skills, and manages to avert the impending clash.
According to Yoon-ki, Geol-jae transferred from a notorious, unnamed school that operated like a juvenile detention center, absorbing the overflow of detainees from overcrowded facilities. This school was notorious for sanctioning fights, with teachers overseeing battles among the students. The students were thrown into group fights where everyone fought, and the last one standing earned a chance to transfer to a normal school. Hence, Yoon-ki deduces that Geol-jae, having joined their school, must have been the last man standing in that brutal competition.
Seung-ki, frustrated upon learning that his orchestrated fight never materialized, hatches a plan with his gang to ambush Geol-jae after school. Geol-jae, under strict orders not to fight and risk losing his hard-earned opportunity, takes off as soon as he spots Seung-ki tailing him. The gang, assuming he's fleeing, gives chase.
But Geol-jae wasn't running away; he was luring them away from the school to a secluded spot where he could teach them a lesson without getting caught. Seung-ki and Sung-wook land no blows on Geol-jae, who swiftly and effortlessly leaves them battered and unable to stand. Yoon-ki, seizing the opportunity, films the fight and later uses it as leverage to negotiate with Geol-jae. He tells Geol-jae that he owes him a favor and should be ready to help him in the future when needed.
During class, Ui-Gyeom's mind drifts as he repeatedly recalls Geol-jae's words from the rooftop encounter. Ui-Gyeom had insisted that they only fought the bad guys, to which Geol-jae had retorted, asking how he differentiated good from bad. Could he really label Geol-jae as a good guy? And what about himself, Ui-Gyeom? Lost in these thoughts, Ui-Gyeom fails his exams.
Later, at home, his father, Seok-tae, unleashes his fury upon learning of Ui-Gyeom's failure. Seok-tae is livid that Ui-Gyeom has been skipping classes, arriving late, and now failing exams. In a fit of anger, he slaps Ui-Gyeom. Da-bin steps in to defend her brother, telling Seok-tae that his methods of discipline are misguided. She pleads for communication instead of conflict and urges him to stop pressuring Ui-Gyeom.
That night, Ui-Gyeom and Yoon-ki find themselves facing another gang of bullies. After saving some students from the bullies, the rescued students capture the fight on video. In the heat of the moment, one of the bullies attacks Ui-Gyeom with a rod. Ui-Gyeom, consumed by rage and haunted by memories of his father's harsh discipline, unleashes a relentless barrage of blows, ignoring the bully's pleas for mercy.
