In a secluded psychiatric facility in Estonia, Esther, a cunning and manipulative patient with a condition that makes her appear much younger than her actual age, orchestrates a daring escape. Posing as a missing American girl named Esther Albright, she manages to infiltrate an affluent family by convincing them that she is their lost daughter. The family's mother, Tricia, and father, Allen, are elated yet wary of her return. They have faced emotional turmoil since their daughter's disappearance and see Esther's return as a glimmer of hope. However, the family's reunion is tainted by the lurking suspicion that the girl they welcomed into their home is not who she claims to be.

As Esther attempts to integrate into this seemingly perfect family, she finds herself contending with a set of unexpected and complex dynamics that threaten to expose her dark past. Her relationship with Tricia becomes particularly strained as the mother begins noticing unsettling inconsistencies in Esther's behavior and story. The blend of suspense and psychological tension escalates as each interaction chips away at Esther’s carefully constructed façade. Meanwhile, the family grapples with the resurfacing of past secrets and unaddressed animosities. As Esther manipulates and schemes to maintain her cover, she must deal with challenges she had not anticipated in pursuit of her goal, leading to an intense and unpredictable showdown.