Ryu, a stoic man restricted by his deafness and muteness, finds himself laboring in a factory, trapped in a monotonous existence. His frail sister, on the brink of death, desperately requires a kidney transplant, leaving Ryu in a state of urgency as he explores the murky waters of the black market for organ donations. In a risky move, he reaches out to a shadowy network of underground dealers, offering one of his own kidneys alongside a generous sum of money to find a suitable match. Unfortunately, these dubious players disappear, leaving Ryu feeling exploited and hopeless. Just when a legitimate donor is found, Ryu's hopes are dashed yet again due to the overwhelming financial burden associated with the procedure. It is here that his radical anarchist girlfriend, Yeong-mi, suggests a desperate and shocking plan: to kidnap the daughter of the executive who callously fired Ryu.
Their plan takes a turn when they unintentionally cross paths with Park Dong-jin, a high-ranking executive, as he arrives home to his luxurious estate. A poignant scene unfolds when one of Dong-jin’s former employees, Peng, makes a futile attempt at taking his own life. This event forces Ryu and Yeong-mi to reconsider their initial strategy, ultimately pivoting towards the idea of abducting Yu-sun, Dong-jin's young daughter. As fate intertwines their lives further, Yu-sun finds herself under the care of Ryu's caring sister, setting the stage for a seemingly innocent interaction unmarred by the underlying tension.
The trio's dynamic develops as Ryu constructs a heartfelt necklace for Yu-sun, intricately designed with beads and seashells that reflect her dire situation. Ryu's sister dedicates her time to Yu-sun as well, caring for her hair and offering encouraging words while inviting her to visit again, gifting a precious note with her phone number. In a moment of discovery, Ryu's sister unearths termination papers hidden within her brother's pants pocket, revealing a pivotal detail to his former employer. Amidst this unfolding drama, Ryu and Yeong-mi send a ransom demand to Dong-jin, who complies without hesitation.
Tragedy strikes when Ryu's sister, overwhelmed by her own despair, chooses to take her life in a heart-wrenching scene inside their apartment. In a state of grief and obligation, Ryu, along with Yu-sun and his sister's lifeless body, make their way to a beloved riverside spot from their childhood. As Ryu becomes lost in his sorrow, Yu-sun tragically slips into the river, her fate shrouded in an ominous silence.
The revelation of Yu-sun's lifeless body instigates a chain of events, prompting Dong-jin, burdened by guilt, to employ a detective to track down the kidnappers. With a resolve fueled by guilt, he gathers a considerable amount of money through the sale of his company and seeks to untangle this web of events. As the investigation unfolds, the detective discovers Yu-sun's necklace, leading him to suspect Peng holds the key to the entire narrative. However, the shocking news of Peng and his family's tragic end leaves only a faint glimmer of hope: their barely alive child is rushed to the hospital.
Dong-jin's pursuit of the truth leads him down a path filled with heartache as he realizes the extent of the devastation. Within the walls of Ryu's empty apartment, he encounters a local radio program featuring a letter written by Ryu, pouring his heart out about his sister's tragic demise. As Dong-jin connects the dots, he visits the radio station, where he uncovers a haunting painting by Ryu, symbolically illustrating his sister's burial alongside Yu-sun's tragic end.
As the narrative threads begin to coalesce, Dong-jin's search leads him back to the riverbed, where he encounters a disabled man who inadvertently witnessed the harrowing events. There, he uncovers Ryu's sister's lifeless body, which painfully signifies the dire repercussions stemming from Ryu's desperate choices. The necklace belonging to Yu-sun, once a symbol of hope, now serves as a bitter reminder of lost lives, motivating the detective to dive deeper into the enigma.
In the midst of growing tension, Ryu, armed with nothing but a baseball bat, embarks on a bloody spree of revenge against the organ traffickers responsible for his sister's death. This brutal encounter leaves him with a severe stab wound, further clouding his quest for justice. Meanwhile, Dong-jin unleashes a torrent of electric torture on Yeong-mi, tormenting her before ultimately taking her life. With her final breaths, she expresses regret over Yu-sun's untimely passing and warns Dong-jin that his fate is sealed: the terrorist organization she belongs to will seek fierce retribution. Ignoring her warnings, Dong-jin delivers the final blow, concluding Yeong-mi's suffering in a shocking act of violence. The police arrive shortly after, removing her lifeless body from the tragic scene.
However, Ryu's path to justice is only just beginning. After returning to Yeong-mi’s apartment, he discovers law enforcement clearing away the remnants of his sister's life. Little does he know, Dong-jin is lurking, laying an intricate trap for Ryu that culminates in violence. Utilizing a cunning booby trap, Dong-jin strikes Ryu unconscious and drags him to the very riverbed where Yu-sun met her unfortunate end, cutting Ryu's Achilles tendons mercilessly and leaving him to drown.
As Ryu struggles for survival beneath the rushing water, Dong-jin is confronted with devastating news: Peng's child has died. This news momentarily stirs mixed feelings within him, but they quickly dissipate as he returns to Ryu. With cold precision, he begins dismembering Ryu's corpse, only to be ambushed by the very terrorists Yeong-mi had warned him about. Their swift, brutal retribution sends Dong-jin to his own demise, leaving a chilling message pinned to his chest: the cycle of violence promises to continue unabated. As the shadows of the night engulf the area, Ryu's forgotten remains remain a tragic testament to the harrowing consequences of vengeance and brutality, intertwining the fates of all involved in this dark tale.
