Missing

Divorced Ji-sun struggles to juggle work and her 1-year-old Da-eun while a custody battle rages with her ex-husband. After firing the old Chinese nanny who caused Da-eun to be injured, she hires Han-Mae, a young Chinese woman presented as her neighbor's niece. The arrangement sets the stage for a web of deception.

Ji-sun misses a court appointment; Han-Mae had received the notice but did not inform her. In court, the judge rules against Ji-sun, citing her workaholic schedule and presumed mental instability due to the divorce. Her lawyer advises her to beg her husband to let her keep Da-eun.

Returning home, Ji-sun finds chores undone and Han-Mae and Da-eun mysteriously absent. Calls to Han-Mae go unanswered, and a frantic search through the neighborhood and Chinatown yields nothing. Exhausted, she collapses asleep in her own apartment.

The next morning, Ji-sun learns Han-Mae had come by two days earlier and stockpiled flu medicines for a trip with a baby. The neighbour’s nanny reveals Han-Mae is a stranger paid to be introduced as her niece. The deception widens Ji-sun's fear of losing Da-eun.

Ji-sun's lawyer calls, warning of serious consequences if Han-Mae faked a kidnapping. The realization hangs over her as the clock ticks on Da-eun's safety. The pressure pushes her toward more desperate measures.

A man identified as Park Hyeon-ik tracks Ji-sun down and implies Han-Mae owes him money. He leads her to a Chinatown bar where Han-Mae once worked, and the bar owner promises to call if she or Da-eun surfaces. The moment deepens the mystery around Han-Mae's past.

After Han-Mae's disappearance, Ji-sun receives a call from a man claiming Da-eun is held hostage. She transfers all the money in her account to the supposed kidnapper and is directed to Yeouido Wharf. There, she finds a bag of Da-eun's toys and the police soon arrive.

Ji-sun lodges a missing-person report. The police press her for photos of Han-Mae, but she can't find any. The detective notes forged IDs and burner phones, hinting at a larger network of deception.

Back at home, a security footage expert shows that Han-Mae engineered the accident that injured Da-eun to justify the firing of the old nanny. Ji-sun later returns to the bar and digs through Han-Mae's belongings, discovering a baby photo from Mihwa Studio.

A flashback reveals Han-Mae's past as Mok-ryeon at the same bar, where her first client, Hyeon-ik, secretly plots. She discusses anesthesia and even contemplates organ donation, foreshadowing a darker future. The memory explains her willingness to manipulate circumstances toward a larger goal.

The Mihwa Studio photo trail connects Han-Mae to Jae-in, with credits listing Suk-ho as the father and Kim Yeon as the mother, and a Chungcheong address. Ji-sun travels there and finds an empty house, learning Han-Mae’s history of abuse and abandonment of Jae-in by Suk-ho’s family. The truth begins to surface about why Han-Mae became entangled with Da-eun.

The police close in and learn that Jae-in suffered from Congenital Biliary Atresia and needed a liver transplant. Han-Mae's past as 'The Singing Chinese Woman' is revealed, and the earlier hospital discharge of Jae-in is tied to the scheme. Da-eun's place in the hospital becomes a focal point as the investigators piece together the abduction.

Hyeon-ik explains the money went to Suk-ho to cover Jae-in's care, and that Han-Mae attempted to kill Suk-ho in exchange for Da-eun. She then runs with Da-eun, and Han-Mae even arranges a passport for Jae-in with plans to flee to China. The grim scheme shows the extent of their desperation.

Ji-sun rushes to the port, boards a China-bound ship, and a tense chase unfolds on the hull. Han-Mae realizes she is not with Jae-in and, in a final act, hands Da-eun back to the police before leaping into the sea. Ji-sun follows and saves her daughter after Han-Mae drowns.

Ji-sun wakes in the hospital and is reunited with Da-eun in a playground, where Da-eun calls her 'Mama' for the first time. The family begins to heal after the harrowing ordeal, though the scars remain.