Two women meet on a train. Each is running from a deadly secret. When one disappears, the other decides to take her place-for better, or for worse.Jae-Young has just left everything shes ever known, not that it was much: her thankless job, her infested apartment, and her abusive boyfriend-who happens to be dead on the kitchen floor. Murder was never the way she envisioned leaving, but times were desperate. Now on a train to the bustling city of Seoul, Jae-Young is hoping to escape her transgressions and just become invisible-safe.On the train, she meets a chatty mother fleeing with her infant son from an unfaithful husband and hoping to find refuge with the in-laws shes never met. To avoid further conversation, Jae-Young excuses herself for a moment. When she returns, the woman is nowhere to be found. But her crying child remains with a note, pleading with Jae-Young to take him to his fathers family in a remote province far from Seoul. Its not an ideal pit stop, but for the sake of the child, she cant ignore the request.When Jae-Young arrives, the house takes her by surprise. Its a gated manor oozing with opulence and the finest luxuries-the kind of place she could only dream of setting foot in. Whats more, the family assumes Jae-Young is their daughter-in-law and invites her to stay. She imagines an easy life in their care, free of worry and fear. And Jae-Young realizes: Theres nothing more invisible than becoming someone else.