Francesca Annis gives quite a performance as a pair of identical twin sisters, Delphi and Diane. They are complete opposites in personalities and lifestyles. When Diane is murdered, everybody is a suspect especially Delphi who deals with rare stamps. The film is satisfactory even with a stellar cast. They filmed on location in England. Jack Cardiff tried his hand at directing. The film is a decent effort. The mystery does have some twists especially at the end of the film. I wished the film had a better ending. I would have liked to know what happened to the main characters in the aftermath. James Booth plays detective in the film. I enjoy seeing other British actors and actresses like Nicky Henson, Joss Ackland, Una Stubbs, a young Dame Penelope Keith before she became a television star.