After her mother's tragic death in a boathouse fire, Anna, a young woman, spends ten months in a psychiatric facility. Haunted by nightmares and the painful loss, she finally returns home to her father and her older sister, Alex. Anna finds significant changes in her household, notably her father's new girlfriend, Rachel, who was previously her mother's live-in nurse. Rachel's presence, attempts to integrate into the family, and fast-tracked relationship with her father create an atmosphere of tension and mistrust among the sisters. Anna and Alex find Rachel's behavior and past increasingly suspicious, prompting them to investigate her intentions and connection to their family.

Their pursuit of the truth about Rachel unearths disturbing secrets and a series of mysterious events that suggest their mother's death was not an accident. The sisters' quest for answers leads them deeper into a tangled web of deception and hidden motives. As they peel back the layers of Rachel's facade, Anna struggles with her trauma and the realization that their lives have been irrevocably altered by their mother's passing. The sisters' bond strengthens as they face the unfolding mysteries, with Anna seeking closure and a way to protect her family from a potential threat that could destroy them from within.