Episode 2 of Season 1 of "The Defects" opens with a haunting flashback to the day So-mi was reluctantly reclaimed from her dreams. She had dared to skip school in favor of an audition, only to have her mother discover her absence and drag her back home in disgrace. Seeking solace, So-mi unloaded her frustrations onto her father, Chul-soo, who, instead of offering comfort, exploited her vulnerabilities through hypnosis and committed a despicable act of sexual abuse.
In the present, the children are still grappling with the tragic loss of Tae-sik. So-mi, consumed by grief and anger, lashes out at Si-woo, unfairly blaming him for their plight. A-hyeon, recognizing the futility of So-mi's accusations, slaps some sense into her, calming her down momentarily. Just as tensions were easing, two menacing figures in black suits arrive, seeking Si-woo. Fortunately, they are thwarted by the locked door, and the kids observe their failed attempt from the safety of surveillance cameras.
After their departure, A-hyeon, her heart heavy with memories, recalls her poignant farewell with Tae-sik. As she sorts through his belongings, she stumbles upon a safe containing firearms, a recorder, and a cache of evidence Tae-sik had painstakingly gathered. Among these treasures, she finds a poignant letter from Tae-sik, confessing his knowledge of his actions and the burden of guilt he bore. He justifies his decision to shield the kids and seeks redemption. Upon playing the recorder, A-hyeon listens to the harrowing reasons behind the parents' decisions to return their children, each citing unsatisfactory qualities.
Elsewhere, Se-hee is denied an audience with a powerful chairman, while Jung-hyeon stands by, observing the police investigate Tae-sik's fatal accident from afar. He receives a call and speeds to the last known location of Si-woo, which coincides with the children's hideout. Before they flee, A-hyeon delivers an emotional speech, urging them to embark on a new journey, hoping they'll follow through with Tae-sik's relocation plan.
As they converse, Jung-hyeon and his men initiate the demolition of their house. The kids scatter, but not before catching the attention of Jung-hyeon and his men. Amidst the demolition chaos and a gas explosion, Si-woo sustains injuries. A relentless pursuit ensues, but the kids narrowly escape. Jung-hyeon views this as a damning failure of his team's competence.
Meanwhile, Se-hee meets with a new influential client eager to procure the perfect child. At Si-woo's school, rumors about his disappearance swirl, with some speculate that his mother had him institutionalized and faked his disappearance. Se-hee's daughter worries silently, too afraid to confront her mother but confiding in Jung-hyeon, whom she affectionately calls uncle. He encourages her to focus on her studies, reinforcing the mantra that victory is paramount.
The kids endure hours of arduous trekking to reach the man Tae-sik promised would aid them. He welcomes them with dinner and money, only to betray their trust, leading them into a trap and abandoning them at the port.
Upon catching sight of Jung-hyeon and his henchmen, the children scatter in all directions like frightened birds. A fierce skirmish ensues as the kids fend for their lives, their every move imbued with the combat skills Tae-sik had so diligently imparted to them. So-mi and Joo-an deploy fireworks, casting a dazzling array of lights to divert the assailants' attention. Meanwhile, Seok-su guards Si-woo with steadfast resolve, while A-hyeon, brave and resolute, confronts Jung-hyeon single-handedly. In a dramatic turn of events, she manages to subdue him and seize his firearm, leaving him astonished when she spares his life. The remaining children, swift and resourceful, hotwire a car, scoop up A-hyeon, and speed away into the night.
They hole up in a secluded motel, their conversations hushed as they strategize their next course of action. A-hyeon unveils the cache of evidence Tae-sik had painstakingly gathered. The revelation of their parents' paltry excuses for abandoning them cuts deep, stirring a shared sense of betrayal. Determined to complete Tae-sik's unfinished business, A-hyeon declares that it's time to uncover the final, elusive piece of the puzzle – the colossal monster that haunts their lives.
Among Tae-sik's collected photographs, they notice a enigmatic black card that piques So-mi's recognition. With renewed purpose, So-mi and A-hyeon embark on a stakeout of Chul-soo, now serving as the principal of a school. They trail him discreetly to a bar where he indulges in drinks with his fellow educators, the ambiance thick with camaraderie.
Later that night, they make their move, and A-hyeon adopts the guise of his designated driver. During the ride, Chul-soo, unable to contain his vulgar curiosity, peppers her with questions about her age and engages in revolting self-gratification, revolting both A-hyeon and the very fabric of decency.
Upon reaching his home, Chul-soo persistently demands to learn A-hyeon's age, fueling an awkward curiosity. A-hyeon, playfully indulging him, teases that she'll do anything for a few coins, which sets off alarm bells in Chul-soo's perverted mind. He reveals a disturbing preference for underage girls, prompting A-hyeon to offer a deceitful solution: introducing him to her supposed underage friend. Enter Joo-an, donned in a women's outfit, seamlessly blending into the charade. Meanwhile, Jung-hyeon dispatches his team to spy on the previous guardians of the children, anticipating any potential contact.
Joo-an expertly diverts Chul-soo's attention while the other children stealthily infiltrate the house. With Chul-soo successfully neutralized, they bind him to a chair and interrogate him about the mysterious card. So-mi, overcome with raw emotions, demands to know the whereabouts of her mother.
A poignant flashback transports us to the harrowing day So-mi was abducted. Soon after Chul-soo's despicable act, So-mi received a heart-wrenching message from her mother, requesting a meeting outside. Tragically, the kidnappers lay in wait by the gate, snatching So-mi away from her mother's desperate embrace.
After enduring a grueling session of torture and threats, Chul-soo finally caves in, confessing that So-mi's mother is confined in a mental hospital. Unaware of Chul-soo's deceitful return of So-mi, she lost her sanity in an endless quest to find her daughter. This revelation plunges So-mi into an abyss of despair, her anger and vengeance directed at Chul-soo. Realizing she has unfairly blamed her innocent mother, So-mi brandishes a gun at Chul-soo, demanding the name of the hospital. A-hyeon and the others frantically try to calm her, but the situation quickly spirals out of control. The episode concludes with a gunshot echoing through the air, So-mi's voice rising in a尖叫 of intent: "I will kill him."
In the epilogue, Se-hee reassures her daughter that Si-woo will be alright, but a closer inspection of her bag uncovers a startling detail: Se-hee's daughter, too, bears the name A-hyeon, evident from the name tag dangling from her school bag.
