Episode 20 of "Seoul Busters" kicks off with a haunting flashback to a pivotal moment 22 years prior, revisiting the lives of the two students initially introduced in episode 17. The revelation unfolds: Hyun-woo, once a mere schoolboy, was driven by envy to shove his friend Hyun-joo into the path of an approaching truck. Now, as Hyun-woo drives Min-seo up Songnae Mountain, he unburdens himself, confessing his crime against Hyun-joo and justifying his intention to eliminate Min-seo, who possesses incriminating evidence against him.
However, Min-seo's apparent compliance was merely a clever ruse. Far from being lulled into slumber by the energy drink Hyun-woo proffered, she had switched it when his guard was down. This strategic maneuver was part of a meticulously crafted plan devised by the team after delving into Hyun-woo's background. Jong-ryeok had infiltrated Hyun-woo's abode, stealthily collecting DNA samples and uncovering sentimental items Hyun-woo had been clutching onto, including Ja-ein's bracelet—a discovery that cemented Yu-bin's suspicions. Moreover, Jong-ryeok stumbled upon the energy drinks and narcotics Hyun-woo surreptitiously used to lace them.
In parallel, Tan-sik shadowed Hyun-woo to the gym, on a quest to uncover any physical marks left by Hyun-joo's cat, which had scratched the killer. They found the crucial DNA evidence embedded in the cat's paws, linking everything back to Hyun-woo. Min-seo's role was arguably the most daunting: to entice Hyun-woo into their trap, a task she eagerly embraced. In a dramatic twist, she leaps from the car and sprints towards the crime scene, where her teammates await.
Confronting Hyun-woo, the team finds him resisting arrest. Fortunately, they were prepared for this contingency, employing a net to ensnare him. The tension mounts as justice finally closes in on Hyun-woo, with every thread of the intricate web tightening around him.
Hyun-woo harbored a bitter jealousy towards Yu-bin's bliss, unable to stomach the notion of Yu-bin triumphing in love. The old saying, "Misery loves company," painted a perfect picture of Hyun-woo's mindset. His cunning plot to incriminate Jun-ho by murdering other women ultimately fell flat. During a prison visit, Hyun-woo unloaded his confession to Yu-bin without a hint of regret. Yu-bin, though wounded, responded that Hyun-woo's actions inadvertently led him to forge four new, cherished friendships. This revelation irked Hyun-woo, who believed he could crush Yu-bin by revealing the graphic details of Ja-ein's murder. His twisted desire was to isolate Yu-bin in a life of sorrow, devoid of loved ones and companionship.
However, Yu-bin had already suspected Hyun-woo and had relocated to Korea with the intention of apprehending him. He had been amassing evidence against Hyun-woo, suspecting him of deeper involvement in numerous homicides. Thanks to Yu-bin's relentless pursuit, Hyun-woo faced a lengthy incarceration.
Upon solving the case, the team joyously welcomed Jung-hwan back, whose optimism about a swift return shone despite his ongoing recovery. They were later honored for their bravery and dedication.
Months later, Yu-bin's transfer to the financial crime department stunned his team, as he had failed to mention it beforehand. Struggling to find his place in the new setup, Yu-bin encountered skepticism from his new colleagues, who perceived him as aloof. Yet, Yu-bin harbored no ill will; he simply cherished the bonds he had forged with his former team, considering them sufficient companionship.
A year has passed since Yu-bin bid farewell to his former team, and it is during this interval that he crosses paths with Hee-ryong, the commissioner, who is actively seeking to assemble a fresh, specialized unit to tackle an emerging case. Hee-ryong holds Yu-bin in high esteem and desires him to spearhead this new venture. Yu-bin, intrigued, agrees to take the helm but stipulates that he has the autonomy to handpick his team members. With a glint in his eye, he reveals to Hee-ryong that he has a select few individuals, each possessing a unique charm, already in mind.
The episode draws to a close with a scene where the newly formed team is delivering a presentation at a school. As anticipated, their charming yet quirky demeanor leads to a series of hilarious blunders, leaving the audience in stitches.
