A sinister Gothic tale in the tradition of The Woman in Black and The Fall of the House of Usher

1891. In a remote and crumbling New England mansion, 12-year-old orphan Florence is neglected by her guardian uncle and banned from reading. Left to her own devices she devours books in secret and talks to herself - and narrates this, her story - in a unique language of her own invention. By night, she sleepwalks the corridors like one of the old house's many ghosts and is troubled by a recurrent dream in which a mysterious woman appears to threaten her younger brother Giles. Sometimes Florence doesn't sleepwalk at all, but simply pretends to so she can roam at will and search the house for clues to her own baffling past.

After the sudden violent death of the children's first governess, a second teacher, Miss Taylor, arrives, and immediately strange phenomena begin to occur. Florence becomes convinced that the new governess is a vengeful and malevolent spirit who means to do Giles harm. Against this powerful supernatural enemy, and without any adult to whom she can turn for help, Florence must use all her intelligence and ingenuity to both protect her little brother and preserve her private world.