Richard and Lelia`s child is conceived in a moment of giggling chaos as they dress for a Christmas party. They arrive rudely late and still glowing, and barely register a slight, drab woman in the hall. Sylvie. As their baby grows, so does the presence of Sylvie - she seems to be nowhere, yet everywhere, harmless yet sinister. Richard is seduced by her subtle, inexplicable charm, while Lelia, struggling with Richard`s sudden ambivalence towards their baby, finds that she is haunted by painful memories. And Sylvie remains as invisible as she wants to be - that is the source of her power. Beware of mice.