Deadly Illusions

Mary Morrison, a successful thriller author, is asked by her publisher to write another book and is offered a two million dollar advance. She initially declines but reluctantly accepts after Tom reveals he lost half their reserves on a risky investment. The decision raises the stakes for her personal and professional life.

Elaine suggests hiring a nanny to help with the kids as Mary writes. After a few interviews, Mary hires Grace. Grace's presence begins to influence Mary's writing and emotions.

Mary struggles with writer's block but finds inspiration in her blossoming friendship with Grace. She experiences what feel like sexual fantasies about Grace and dreams of Grace and Tom in the kitchen. She can't tell if these visions reflect reality or imagination.

Mary confronts Grace and Tom at the dinner table in a tearful outburst, upsetting the children and creating tension. The incident deepens Mary's paranoia about her relationship with both Grace and Tom. Family discord follows.

The next morning, Mary apologizes to Grace for her outburst, blaming overwork. She calls the nanny agency to confirm Grace's status, only to learn there is no Grace in their service. The confusion seeds questions about Grace's true identity.

Mary goes to Elaine's house and discovers Elaine murdered, a pair of scissors buried in her neck. To Mary's shock, the police treat her as the prime suspect. Investigators reveal incriminating evidence, including a video that appears to show Mary arriving at Elaine's house with her face obscured.

Mary travels to Grace's hometown to learn more about Grace's past. Grace's aunt reveals that Grace was abused as a child by her parents, and notes Grace's own troubling behavior. Mary tries to warn Tom, but his phone goes unanswered.

Back home, Tom is in the shower when Grace enters, wearing lingerie and wielding a large knife. She alternates between her gentle, soft persona and a violent alter ego as she attacks Tom. Mary arrives to find Grace claiming she doesn't know what happened, muttering that she 'couldn't stop her' while her alter ego 'Margaret' attacked Tom.

Mary knocks Grace unconscious and stops the attack. The incident confirms to Mary and Tom that Grace is not just a harmless nanny, but a person with dissociative identity disorder. The police later confront the idea that Grace's alter identity was responsible for the violence.

In the aftermath, Grace is placed in a mental hospital for treatment of her dissociative identity disorder. Mary faces the emotional fallout of the events and begins to process her own role and fears. The case leaves them all changed.

One year passes and Mary returns to Elaine's grave to leave the finished manuscript that Elaine urged her to write. She reflects on Elaine's influence and the renewed purpose her writing now holds. The moment marks a tentative closure for Mary.

Mary visits Grace in a mental hospital, continuing to seek some sense of closure. The film ends with Mary leaving the hospital, her face obscured by a headscarf and sunglasses, echoing the disguise from the police video.