Lizzie, a woman who is deeply grieving the loss of her infant daughter several years earlier, becomes increasingly convinced that a young girl she encounters is her own child. This fixation begins to consume her, affecting her relationship with those around her, including her ex-husband Mike and her teenage son Thomas. As she watches the girl, Lola, from afar, Lizzie's suspicion grows, leading her to believe that Lola might have been mistakenly given to another family.

Lizzie's obsession drives her to interfere in the lives of Claire and Bernard, Lola's parents. She undertakes actions that grow progressively more intrusive and desperate in an attempt to uncover the truth. As Lizzie continues to spiral, her behavior escalates, leading to intense confrontations and consequences that impact all involved. Through these events, Lizzie's grief and desperation become palpably clear, raising questions about the limits of a mother's love and the depths of human despair.