Alice, a sweet young woman, arrives to a rich family that is hiring au pair girls to take care of their children and housework. The first night, she hears noises and discovers the master making love with one of his lodgers and his wife on the stairs. She soon realizes that sex is an essential part of life at the castle. Each evening, Alice writes her secrets in her secret diary : a man who sodomizes her in the middle of the night in her bed, the master of the house who gets it on with another au pair girl while the mistress of the house directs these menages a trois. But is it the product of her vivid imagination or a true description of the lubricious activities that are going on?