 From simply the remains of the three girls, she follows the clues which include a frightened old lady, a crazed man with a S&M fetish, and finally a girl who has been subjected to so much sexual torture, she develops a taste for it herself.At the end of the book, Reichs writes that her inspiration for the plot was three skeletons she was sent to investigate that were found in a pizza parlor basement.The girls' bones showed that they had died before 1955 so there was no police investigation into the deaths.