Durtal owns a hotel specializing in honeymoon nights. Thanks to mirrors without stains he stare every night the encounter of participating couples, his servants (a lady's maid and a groom) or his own person. One night, a trade representative mislaid refuge to the hotel of which she discovers the secrets. Beckoning, she asks to stay and becomes the third servant of the hotel. A classic of cinema X French left with a triumphant success on November 15, 1978 in the ALPHA-FRANCE Movie theaters.