Forgotten

Jin-seok moves in with his mother, father, and older brother Yoo-seok. The father warns that one room contains the belongings of the previous owner and that they must not enter it. That night, rain taps the windows and an uneasy silence settles over the house.

That night, Yoo-seok is dragged into a waiting car during a downpour, leaving Jin-seok alone and terrified. The family searches helplessly for his missing brother as the mystery of the house looms. The incident marks the first fracture in the seemingly normal household.

Nineteen days later, Yoo-seok returns home with no memory of where he has been. He behaves oddly, and Jin-seok senses a change in his brother's personality. The unresolved abduction fuels Jin-seok's growing suspicion.

Jin-seok notices signs of artifice in Yoo-seok's behavior and doubts Yoo-seok's identity. He suspects that his brother is not truly who he says. The sense of danger inside the house pushes him toward uncovering hidden truths.

The restricted room becomes the focal point as the family tries to reenact the murder they fear. A psychiatrist plans to hypnotize Jin-seok and stage the events from 1997, with Yoo-seok as the 'father' and an actress as the mother. The plan is meant to unfold on the next rainy night, but a police arrest throws a wrench in the scheme.

The illusion deepens as the plan proceeds: the psychiatrist plays as the father, the actress plays the mother, and the room is used for the staged murder. They wait for the rain to begin the reenactment proper. Meanwhile, the forced performance weighs on Jin-seok and those around him.

Before the reenactment can proceed, Choi is arrested by police for assault and fraud, forcing the trio to postpone the next rainy-night plan. They must continue the act to avoid exposure while the investigation continues. Tension rises as time runs out.

In a tense escape, Jin-seok evades Choi during a pursuit, and a van crash leaves him gravely injured. He wakes in hospital with memories of 1997 flooding back. The past begins to redefine his present understanding of the family.

Flashbacks reveal Jin-seok's real parents and Yoo-seok waiting in a car by the river. A car crash kills his parents and mortally injures Yoo-seok, while the financial crisis makes funding his brother's surgery precarious. Desperation pushes Jin-seok toward a dangerous, morally fraught choice.

Under pressure and financial strain, Jin-seok accepts a message offering money to kill a mother, provided the children are left unharmed. He travels to the house, but his conscience inhibits him from going through with the act. The situation spirals when the mother screams and the daughter sees the knife, escalating the violence.

The doctor father is revealed to have plotted murders to claim insurance during the crisis. Jin-seok confronts him, leading to a struggle in which the doctor accidentally falls to his death. The brutal truth behind the killings begins to surface.

Back in the present, Choi reveals that he is the doctor's son whom Jin-seok spared twenty years earlier. Jin-seok lies to take full responsibility for the killings, but Choi remains unconvinced. The confrontation deepens the emotional and psychological stakes.

Overwhelmed by guilt and the truth, Jin-seok poisons himself and dies. Choi, unable to cope with his own trauma, jumps from a hospital window and also dies. The two deaths close a fatal loop of memory, murder, and consequences.

In a final recollection from 1997, Jin-seok is stopped by a little boy who offers him a lollipop. Declining, he watches the doctor's family walk away together and smiles peacefully at their departure. The ending suggests a quiet acceptance of the traumatic truth across time.