After the separation of her parents, Martha is forced to move to the country, in the old family house where her mother grew up. The situation is already distressing, but it takes a downright disturbing turn when the teenager begins to receive anonymous messages. Threatening messages ordering him to reveal the dark secret his family hides. Is this a bad joke from the young people around? A simple recipient error? Or does her family really have something to hide? Helped by her cousin William, Martha will try to see clearly. It is at the risk of their lives that the two young people will discover the truth.