Wife and husband tied up and gagged

Middle-aged couple Helma Christina and Heinz-Georg Frauenknecht are watching a crime film in their living room on a late Saturday summer evening. They are already wearing their bright coloured silk pajamas and Mrs Frauenknecht is nestling against her husband's chest in search of protection when in the crime film a female police commissioner and her male collegue get captured, tied up and gagged by some criminals. Mrs Frauenknecht gets always aroused when she watches some bondage scen on TV, especially when a couple of lovers is involved. And later on they couple has a great bed-time. 
They are so captivated by the movie that they don't become aware that a shadow has entered through the open French window ... And then it's really crime time for the bondage loving couple...