Set in 1945 in a remote countryside mansion on the British Channel Islands, the film follows Grace Stewart (Nicole Kidman), a deeply religious woman who lives with her two young children, Anne and Nicholas, who suffer from a rare photosensitivity condition — they cannot be exposed to sunlight.

Grace maintains a strict set of rules in the house: curtains must remain closed at all times, and silence is essential. After the arrival of three new servants, Grace begins to notice strange and inexplicable occurrences — doors opening on their own, voices with no source, and the children claiming to see a "boy" named Victor.

As Grace investigates these events, her grip on reality begins to unravel, leading to a chilling twist that redefines everything you thought you knew.