Plot Summary:On a Christmas night, an ex-convict ,Robert Herbin, meets a beautiful Italian married woman Marthe Drévet ,who has got a lot of things to hide . She lives in an old house ,the first floor of which is a big workshop where a service elevator leads to the apartment.Marthe takes Robert to her home for a drink;he puts a small bird he bought on the Xmas tree,and they go for a stroll in the streets;when they come back,there's a dead body in the room(the husband) and most extraordinary thing,the bird has disappeared.