Aftersomeyearsoftension,RichardCliveOwenbeginsasexualrelationshipwithhissisterNatalieSaskiaReevesNowmarried,therelationshipprovesdangerouslyobsessionalTheirprivateintensity:workingclassoriginscontrastwiththemiddleclass,inhibited,stuffypublicscenesweseeintheRichmondworldintowhichNataliehasmovedwithhermarriageAstheguiltandintensityofthesiblingsincreasesweseemtobeheadingfordisaster,aforbodingwhichincreaseswhenNatalie'shusbandSinclairfindsout