Architect Tom Faraday is determined to finish the home he's building in Norway, in the same place where he lost his wife, Aurelia, to suicide. Lexi Ellis takes a job as his nanny and immediately falls in love with his two young daughters, especially Gaia. But something feels off in the isolated house nestled in the forest along the fjord. Lexi sees mysterious muddy footprints inside the home, and then Aurelia's diary appears in her room one day. Gaia keeps telling her about seeing the terrifying Sad Lady, and soon Lexi suspects that Aurelia didn't kill herself, and that they are all facing something far more sinister lurking around them.