Episode 10 of "Nine Puzzles" kicks off with a thrilling twist as Kwon meets his untimely demise. I-na and Han-saem, amidst the grief, secure the latest puzzle piece and uncover a shocking revelation: Yang's presence at The One City following Yoon-su's brutal murder. The duo ponders whether the elusive killer resides or operates within the confines of the complex.
I-na's investigative prowess leads her to the crime scene, where she meticulously analyzes the evidence and concludes that Yang is not an accomplice but rather, someone who tried to thwart the killer's deadly plans. Intriguingly, the killer displays a peculiar fondness for Yang, opting to save him rather than executing Kwon immediately.
At the precinct, the cops debrief on Kwon's cause of death – poison administered through an IV drip, hinting at the killer's medical expertise. I-na's suspicions hone in on Dr. Hwang, prompting her to stake out his clinic nestled within The One City. In a bold move, she sneaks his keys and infiltrates his private domain, finding it eerily empty. Unexpectedly, Dr. Hwang calls Han-saem from an anonymous payphone, posing the question: Could the puzzle sender be the killer themselves?
The police spring into action, reviewing CCTV footage to unmask the caller's identity. Meanwhile, back at Dr. Hwang's abode, a chaotic scene unfolds – paintings lie scattered everywhere, each bearing his distinctive 'H' signature. I-na grips the latest puzzle piece, her eyes widening as she spots the familiar moniker amidst the artwork. The realization dawns: Dr. Hwang knows the killer and has intentionally crafted these puzzles to guide them.
Reflecting on her journey, I-na recalls receiving the puzzle pieces only after Mi-young's tragic murder. The depth of her obsession with Dong-hoon's puzzles was known only to a select few – Dr. Hwang In-chan and Dr. Lee Seung-joo. Yet, among them, Lee is the one who knows her best, her closest confidant. A chilling realization strikes I-na: Dr. Lee Seung-joo is the killer.
As I-na dashes out in a hurry, her eyes catch sight of Lee's room door ajar, revealing a chaotic scene filled to the brim with an assortment of toys, masks, balloons, and intricate puzzles. Among them lies another puzzle piece meant for I-na – a king figure encircled by a menagerie of insects, whispering secrets of its own.
Hwang is ushered in and admits under interrogation that Lee had tasked him with creating an illustration. His loyalty to her remains steadfast, making it difficult for him to entertain the notion that she could be a murderer or toy with I-na's emotions so callously. Meanwhile, the police are on a desperate manhunt for Dr. Lee, whose whereabouts remain unknown. Adding to the intrigue, Assemblyman Kim Mu-ryoung, a former infrastructure minister, has also vanished without a trace.
This time, I-na turns her inquisitive gaze towards Hwang. He remains uninvolved out of gratitude for Lee's discretion in keeping his sexual orientation confidential. The sole fragment of information he possesses dates back a decade when a policeman approached Lee during her student days, prompting her to take a year-long sabbatical. Lee's world is a solitary one, with I-na as her sole companion and Sergeant Nam Na-ri as the only other acquaintance.
Nam, who shared a school with Lee, recounts her as an enigmatic figure, unapproachable and aloof. Their sole conversation transpired during a school trip to an amusement park that both skipped. In a rare moment of vulnerability, Lee casually revealed that her mother had deserted her at a tender age, vowing to exact revenge should she ever cross paths with her again.
I-na and Han-saem piece together the puzzle, deducing that Yang's encounter with Lee must have unveiled something profound, triggering her to embark on a murder spree a decade ago. This realization haunts Yang, leading him to blame himself for the unfolding tragedy.
In search of clarity, I-na visits a private investigator specializing in missing children cases. Their investigation uncovers a haunting poster of a seven-year-old Lee Seol, vanished from the magical realm of Dream Land. Her mother, Lee Nam-suk, has tirelessly searched for her, her last known address etched at the Seo-jin Diner within the bustling Shindonga Market – a place where Yang once worked. The demolition of the diner was marked by a sensational incident that captured headlines, forever etching its memory in the minds of those who witnessed it.
The scene transitions to a haunting flashback. The Shindonga Market, now marked for redevelopment, stands as a relic of the past, soon to be replaced by the grandeur of The One City. A resilient faction of owners, led by the indomitable Lee Nam-suk, refuse to vacate their beloved premises. Among them, Mi-young, a storeowner who has embraced the impending change, finds herself caught between loyalty and expedience; her boyfriend, Chi-mok, serves as the subcontractor tasked with the demolition.
Yang, observing Mi-young's attempts to persuade Nam-suk to relocate, scolds her fiercely when the elderly woman stands her ground. Nam-suk harbors a heartfelt hope that by staying, her estranged daughter might one day find her way back. Meanwhile, Yoon-su, unyielding in his stance, refuses to compensate Chi-mok until the site is cleared without delay.
One fateful night, Chi-mok and his henchmen storm the market, wielding Molotov cocktails like torches of chaos, forcing the reluctant owners out through a blend of intimidation and violence. Yang and Nam-suk, among those who refuse to budge, suffer the brutal consequences. Chi-mok, blaming Nam-suk for the delay, lays hands on her roughly. As a fiery inferno descends upon them, he abandons her in her hour of need, fleeing the scene.
Cheol-jin, the lead constructor, leverages his connections within the police force to ensure no interference halts the riot and the flames' unchecked spread. Dong-hoon, colluding with corrupt forces, ensures that the tragic demise of Nam-suk is swept under the rug, avoiding any police scrutiny. Their actions are funded by Assemblyman Kim, who sees the redevelopment as a stepping stone to the mayor's office. Kwon, the chief prosecutor, connives to dismiss Nam-suk's case, further burying the truth.
Reporter Lee, with malicious intent, crafts a narrative that portrays Nam-suk as a greedy arsonist, twisting the tale to fit a darker, more convenient narrative. As Nine Puzzles Episode 10 draws to a close, I-na returns home to an unsettling sight: Dr. Lee, looming in the shadows, his presence a harbinger of unseen truths yet to unfold.
