Crawford secures her a position as lady’s maid in a grand house on the Thames. As Bonnie comes to understand the family – the eccentric Mr Moncrieff, obsessively drawing mausoleums for his dead wife, and their peculiar daughter Cissie, scribbling imaginary love letters to herself – she begins to question what secrets are lying behind the house’s paper-thin walls and whether her own presence here was planned from the beginning.