The House of the Yellow Carpet [La casa del tappeto giallo]

Franca and her husband Antonio decide to sell a yellow rug which was a gift of Franca's stepfather. One day, while Antonio is out, a strange man rings saying he wishes to buy the rug. But the man's visit becames a nightmare. He kidnaps Franca and says he killed his wife on that same yellow rug. Then Franca kills the man. But is that really all that has happened? And who was that strange man?