Episode 4 of "Seoul Busters" kicks off with a nostalgic flashback to the golden days of Joong-Ryeok's boxing career. On the brink of defeat, he stages an incredible comeback, fueled by his coach's unwavering encouragement and strategic advice. Fast-forwarding to the present, Joong-Ryeok stands outside a prison, patiently awaiting the release of a notorious gang leader, engaging in lighthearted chatter with his minions about his triumphant past in the ring.
As Sang-su, the recently freed prisoner, emerges from his confinement, Joong-Ryeok swiftly rearrests him under fresh charges. Sang-su attempts a desperate dash for freedom, only to be swiftly subdued by the vigilant team.
Elsewhere, Yu-bin engages in a catch-up session with the police chief, his path crossing with an old friend who can't help but inquire about the chief's unusual reliance on Yu-bin. The friend alludes to a mysterious incident in America involving Yu-bin, speculating whether he's back in the country to track down a fugitive. It seems the culprit has slithered into Korean soil.
The air thickens with curiosity: what untold tale does Yu-bin's American experience hold? The conversation shifts to Yu-bin's newfound team and their notorious reputation, yet Yu-bin stands firm in their defense, painting them as endearing characters.
As night falls, the team convenes for their inaugural dinner, a chance encounter leading them to Joong-Ryeok's former coach's humble chicken joint. To Joong-Ryeok's amazement, he discovers that Coach Yoon has retired to a life of frying chicken, while Tae-sung, another acquaintance, operates a nearby gym. The trio reunites with heartfelt joy, reliving cherished memories. Joong-Ryeok is doubly surprised to find Coach Yoon's daughter, Hyo-joo, now a blossomed young woman.
Despite the team's enthusiasm for the meal, Yu-bin grudgingly foots the bill, his distaste for the chicken evident. As they pose for a group photo, Yu-bin hesitates, shielding his face as if fearing recognition from an unseen foe. However, his fears seem unfounded as a sudden fire erupts in the restaurant, casting a dramatic end to the evening.
The following dawn, the team's phones erupted with news of the devastating fire, propelling them into a frenzy as they hastened to the scene. Joong-Ryeok's heart was heavy, for this case resonated deeply within him, striking close to his personal realm. Upon arrival, they were met with the grim reality that Hyo-joo had sustained injuries and was rushed to the hospital's care. Without hesitation, Joong-Ryeok raced to the hospital, determined to offer solace to Coach Yoon.
Meanwhile, Yu-bin and the fire brigade embarked on a meticulous search for the culprit behind the blaze, the signs pointing towards a sinister act of arson. The meticulous removal of CCTV cameras from the restaurant only added fuel to the fire of suspicion. Eun Gyeong's forensic insights uncovered that Hyo-joo had suffered a devastating blow to the head, likely from behind, resulting in a concussion—a chilling clue in this intricate puzzle.
As the investigation unfolded, the team cast their net wide, scrutinizing potential suspects. Joong-Ryeok's indignation flared when Coach Yoon's name was dragged into the fray as a potential perpetrator. He lashed out at Jung-hwan, his emotions spilling over, but Yu-bin's steady hand reined him in, reminding them all that no one should be dismissed without due process. He urged Joong-Ryeok to keep his personal sentiments in check, for justice demanded objectivity.
Parallel to this, Tan-Sik stumbled upon a golden lead—footage from a neighboring CCTV camera capturing a shadowy figure lurking near the restaurant mere minutes before the conflagration. This revelation sparked a new line of inquiry, with Yu-bin assigning Tan-Sik and Jung-wan to delve deeper into Hyo-joo's movements on that fateful day. Min-seo, meanwhile, was dispatched to uncover the identity of the mysterious man and interrogate neighboring business owners for any hints of the stranger's identity.
Joong-Ryeok, driven by a mix of duty and personal concerns, shifted his focus to Coach Yoon. He ventured into Tae-sung's gym, where he encountered the part-time worker who had heroically saved Hyo-joo's life and was striving to improve his own circumstances. Learning that the young man's actions had echoed Coach Yoon's own encouragement during Joong-Ryeok's own struggles with boxing, a wave of emotion washed over him. It was a poignant reminder of how Coach Yoon had been his rock, preventing him from abandoning his dreams even when all seemed lost.
After an exhaustive day, Jung-hwan trudges back to the warm embrace of his family, where his wife gently reminds him of their daughter's impending birthday celebration. The little girl's heart is set on a magnificent Tyrannosaurus rex figurine, and Jung-hwan, with a smile and a nod, vows to make her dream a reality.
Meanwhile, in a different corner of the world, Yu-bin's thoughts linger on a serendipitous encounter with a stunning woman amidst the patter of a rainy day. A photograph of her graces his desk, fueling speculation about a tragic turn of events that may have compelled him to search for her tormentor. Is she a beloved wife or a cherished lover? The mystery deepens, leaving us yearning for answers to the unspoken questions that haunt his heart.
The following day brings a glimmer of hope for Min-seo, as he uncovers a vital clue in the labyrinthine CCTV footage. The enigmatic figure turns out to be none other than the proprietor of a chicken restaurant that stands as a rival to Coach Yoon's establishment. Tales of bitter rivalry weave through the streets, whispered by neighboring business owners. Yet, the interrogation of the restaurant's owner yields a frustrating dead end.
On the contrary, Jung-hwan and Tan-sik embark on a revealing conversation with Hyo-joo's friend, unearthing the fact that the girls had attended a lively party before Hyo-joo's fateful decision to study at the restaurant. Joong-Ryeok, delving deeper into the mystery, painstakingly restores Hyo-joo's phone data, uncovering a chilling revelation: she had been researching self-defense weapons and filing reports about a stalker. The pieces of the puzzle begin to take shape, painting a picture of a young woman's courageous fight for safety in the face of danger.
