Cello

The talented cello player Mi-ju withdraws from performing after her friend Tae-yeon is killed. The trauma shadows her music career and she stops practicing. The murder marks the start of a long, uneasy quiet in her life.

Mi-ju's professor tries to coax her back into performing and even offers a professional position. She declines both opportunities, signaling her resolve to stay away from the cello. The insistence foreshadows looming expectations and guilt.

While driving home, Mi-ju hallucinates a student telling her that her music is for nothing and that she will face revenge. The vision unsettles her and blurs the line between reality and fear. It hints at a haunting closer to her door.

Back at home, Mi-ju receives a chilling voice message that deepens her sense of threat. The message seems to come from the unseen forces around her. She grows more wary of what might be following her every move.

Her eldest daughter Yoon-jin's autism is present; the rest of the family behaves as if mute and emotionless, making the party feel eerie. Only Yoon-jin sings 'Happy Birthday' to Mi-ju. The party underscores the growing estrangement and supernatural tension in the home.

Seeking to nurture Yoon-jin's burgeoning interest, Mi-ju buys a cello after seeing her longing gaze. The purchase appears to restore a sense of normalcy, but it also deepen the haunting connection between music and danger. This moment plants the seed for what comes next.

Yoon-hye asks to try the cello, but Yoon-jin's erratic behavior erupts when she bites her sister. The bite underlines the growing tension and suggests Yoon-jin's unspoken distress. It also foreshadows further violence in the household.

Kyeong-ran, Mi-ju's sister-in-law, is quietly murdered by what seems to be a ghost. Nobody else notices, but Yoon-jin witnesses the body hanging at her window. The haunting in the home becomes undeniable for Mi-ju at this moment.

Mi-ju recounts the death of Tae-yeon as jealousy and a car accident, presenting a version where Tae-yeon was the jealous rival. Jun-ki listens, troubled by the revelation. The telling foreshadows the deeper truth that remains hidden.

Yoon-jin's actions lead to Yoon-hye falling from a balcony; to silence the trace, Mi-ju hides Yoon-hye's body in the basement and lies to Jun-ki that she went to camp. The cover-up entwines the family more deeply in the haunting.

Jun-ki discovers the basement secret and confronts Mi-ju. In the ensuing struggle, he is stabbed, and a ghostly presence seems to kill him, with Tae-yeon's name whispered. The tragedy cements the household's downfall.

A flashback reveals that Mi-ju's version of events was not true: Tae-yeon was the more talented cellist, and Mi-ju was the one who envied her. She sabotages Tae-yeon in the car, letting her fall to her death. This revelation flips the audience's understanding of the past.

Back in the present, Mi-ju tries to stab Tae-yeon's ghost to stop her from reaching Yoon-jin. The confrontation leaves her battered and the housekeeper inadvertently stabbed. The supernatural influence tightens its grip on the family.

Mi-ju awakens in the hospital to realize that the preceding events happened while she was in a coma due to the truck crash. Her family is safe, but the truth of the haunting remains unresolved. The twist reframes everything she thought she remembered.

Back at home, Mi-ju finds her family singing again in the attic on her birthday, just as at the start. Inside, a scribbled inscription reads 'This is only the beginning,' and Tae-yeon's ghostly hands grasp her face. The ending leaves the horror open for what comes next.