The Charm School Mystery (Sweet Valley Twins)
Playing detective...When a charm school opens in Sweet Valley,  Jessica Wakefield can't wait to attend. What could be  better than taking classes to learn about clothes,  makeup, and going parties? Jessica's twin sister,  Elizabeth, has no interest in the school at  all--until she uncovers some suspicious things about its  owners. Elizabeth convinces her friends Amy and  Maria to sign up for classes and do some detective  work. But the girls soon realize that charm school  isn't as easy as they thought it would be. What's  more, Amy and Maria are worried that Elizabeth's  sleuthing may put them in real danger. It looks as  if the girls may be in over their heads--in class  and in their investigation!