Episode 11 of "Nine Puzzles" kicks off with a nostalgic flashback, depicting a teenage Lee Seung-joo wandering through the whimsical realm of Dream Land. A decade later, Yang arrives at her doorstep, presenting her with Nam-suk’s photograph and a cherished handkerchief. His quest to locate Dr. Lee had been fruitless due to her name change. Intrigued and inquisitive, she peppered Yang with questions, who then unfurled the entire saga before her.
In the present day, Dr. Lee, alias the Puzzle Killer, introduces herself with a chilling grandeur to I-na, escorting her to the next grim stage of her dark narrative. Meanwhile, Han-saem is plunged into a whirlpool of anxiety as he fails to establish contact with I-na. The police sift through CCTV footage, tracing the women's footsteps to The One City. Upon their arrival, Dr. Lee commits a daring act, pushing Assemblyman Kim off the rooftop. His lifeless body narrowly misses Han-saem, leaving him shocked and appalled at I-na's perilous decision to accompany Lee.
Why does the Puzzle Killer, Dr. Lee, orchestrate these murders as public spectacles? I-na is distressed, feeling manipulated. Lee, however, insists that her intentions were pure; she wanted to aid I-na in unraveling the intricate puzzle. She had halted her grim spree when it seemed no one cared for her tale. But her resolve was reignited upon discovering I-na's relentless pursuit of truth.
A poignant flashback unfolds after Yoon-su's tragic demise, where Captain Yang returns Nam-suk's handkerchief, inadvertently left at the crime scene, to Dr. Lee. He pleads for her to cease her actions, believing it's already too late for redemption. Yang realizes her desire for the world to acknowledge the injustice wrought upon her family, hinting at a press conference as a viable option. Yet, she declines, driven by a burning thirst for vengeance alongside her need for recognition.
In the thick of the present, I-na endeavors to persuade Dr. Lee that murder is not the avenue for justice. The therapist, steadfast in her conviction, counters that none of the perpetrators have shown remorse or apologized. They had conveniently forgotten Nam-suk's demise, a fact that fuels her anger. Additionally, Dong-hoon's revelation that he acquired three apartments to bury the case – later selling them to fund his own home – adds another layer of grotesque irony to this tale of sorrow and wrath.
Why does Dr. Lee take her own life? After murdering Assemblyman Kim, she hands I-na the crucial, yet mysteriously blacked-out, central piece of a larger puzzle and flees the scene. This piece stands as the linchpin of the entire enigma. Dr. Lee is later seen at the funeral home, an expression of remorse etched across her face for Yang's untimely demise. Meanwhile, Han-saem rushes to the scene, while I-na heads to the theme park in a desperate bid to halt the impending final murder.
Fortune smiles upon I-na as she stumbles upon Dr. Lee amidst the whirling carousel. The doctor has drenched the ride in oil, preparing for her final, fatal act. It transpires that she herself is the final piece of the puzzle, intent on sacrificing her life. I-na, mistaking her actions for cowardice, fails to comprehend the depth of her despair.
Lee confesses that she has forgotten the location of the restaurant where her mother awaited her fatefully. In a poignant quest for solace, she frequently visits the carousel, hoping the familiar sights might trigger a memory. Overwhelmed with guilt for her mother's demise while waiting for her at the restaurant, she feels devoid of any purpose to continue living. Han-saem arrives on the scene just as I-na, both of them attempting to intervene and halt Lee's self-destructive path.
Lee remarks coldly that she despises those who struggle to lead lives devoid of meaning. She finds it incomprehensible why one life must be extinguished to pave the way for another. As flames engulf her, Lee perishes in a fiery blaze, leaving I-na and Han-saem standing in stunned silence, witnesses to her tragic, poignant end.
How does the tale conclude for I-na and Han-saem? At the precinct, I-na steadfastly declines to provide a statement, invoking a blanket of amnesia. Han-saem, equally resolute in his compassion, refrains from pressuring her further. She seeks refuge within the confines of her home, while he, undeterred, delivers daily doses of comfort in the form of coffee. He attends Yang's funeral, his heart heavy with remorse, offering an apology for his inability to save Dr. Lee.
A week passes, and I-na contemplates resignation, but Superior Yoon persuades her instead to embark on a well-deserved break. It is during this time that fate brings I-na and Han-saem's paths to cross again. He, with characteristic charm, tries to lure her back with the intrigue of a fresh case. Amused yet intrigued, she eventually finds herself sharing a meal with him and his mother. Over dinner, she discovers that their new apartment in The One City was a stroke of unexpected luck won through a lottery.
I-na's spirits further lift as she embarks on a television interview discussing the enigmatic puzzle case, her playful demeanor resurfacing. She reveals the deeply personal motive behind her career choice as a criminal profiler – to scrutinize her own psyche. She had harbored suspicions that she might be Dong-hoon's murderer and sought to uncover the concealed truths. The interviewer gently probes if she has finally found peace, leaving her momentarily lost in contemplation.
Some time later, Han-saem is confronted with another grim puzzle. Jeon Mi-so, her life's essence drained and her body meticulously adorned, is placed on grim display. Driven by a renewed sense of purpose, I-na returns to her role as profiler, delving into the twisted mind of the killer. As Nine Puzzles Episode 11 draws to a close, she presents Han-saem with yet another perplexing enigma, his disbelief palpable.
