Human Desires, aka Indecent Behavior 4, is one of the worst soft 
  core films I have ever seen. The IMDb score of 3.8 is 
  generous. The major problem is not the mediocre nudity, or the 
  boring simulated sex, but the brain-dead plot.
  
  Shannon Tweed and her philandering husband run a modeling agency, and are 
  holding a pajama party to introduce their three finalists for an important 
  modeling assignment. One of the three, who is also sleeping with Tweed's 
  husband, ends up face down in the pool, after having taken sleeping pills and 
  slashing her wrists. The police declare it an obvious suicide, so one of the 
  other two models, who was also sleeping with the dead girl, hires a private 
  detective, and tries to convince him it was really murder. 
 
 
  
  
  
 
 
 
 
  
 
 
 
  
 
  
 
 
  
  
  So far, a pretty standard plot for a poor whodunnit. 
 
 
  
  
  
 
 
 
 
  
 
 
 
  
 
  
 
 
  
  
  But get this. It turns out that the woman who hired the detective committed 
  the murder. Why on earth would she have hired someone to prove murder when the 
  police considered it a closed case? It seems that they must have changed the 
  script several times and paid no attention to whether all the final bits and 
  pieces meshed properly.
  
   
 
 
  
  
  
 
 
 
 
  
 
 
 
  
 
  
 
 
  
  
  
          
                If you are not familiar with our grading system, you need to 
                read the 
          explanation, because the grading is not linear. For example, by 
                our definition, a 
                C is solid and a C+ is a VERY good movie. There are very few Bs 
                and As. Based on our descriptive system, this film is a:
                D