Teenage detective Nancy Drew finds herself in danger when she sets out to track a jewel thief. She is staying at a family friend's new venture, a summer resort named Lilac Inn which is not far from River Heights. Strange things have been happening, including the aforementioned jewel theft.

Librarian's note: the characters, settings, description, and other details have been done for the first five of the 1980s/1990s editions: #1, The Secret of the Old Clock, #2, The Hidden Staircase, #3, The Bungalow Mystery, #4, The Mystery of Lilac Inn, and #5. The Secret of Shadow Ranch. Librarian needed for #6 and on!