The Clue of the Velvet Mask is the thirtieth volume in the original Nancy Drew Mystery Stories series. It was Mildred Benson's final ghostwrite for the series. The plot and story take place largely in Nancy's hometown of River Heights. Nancy tries to solve a mystery about a gang of event thieves robbing homes during parties, lectures, musicals, and other social occasions planned or catered by Lightner's Entertainment Company. Much of the original story contains elements of dramatic crime dramas; the villains are darker in tone than many other entries in the series. Source: Wikipedia (en)