When the Nancy Drew Clue Colloquium converges on Castleton Manor in Lighthouse Bay, Massachusetts, scholars and fans, dressed as their favorite detective, arrive in their 1930s roadsters. But it turns into a bumpy ride when Nancy A. and Nancy Z. — the good-natured bad girls of Nancy Drew fandom — start pulling pranks. Their group, the River Heights Roundtable, clashes with the Nancy Drew Clue Society, and librarian Faith Newberry strives to keep the peace between the two rival groups.

The event takes a sinister turn when an ominous letter arrives and mysteries from the Nancy Drew series leap out of the books and into real life. As Faith puzzles over what is true and what is fiction, an even bigger mystery unfolds. One of the guests is found dead.

Was the death a terrible accident? Or was the guest murdered? Faith and her chums in the Candle House Book Club get to work sleuthing out clues. But their snooping uncovers more questions than answers, and Faith fears they will never solve this whodunit in time.

Fortunately, Faith's clever tuxedo cat, Watson, lends a paw to their investigation. His keen discovery sends Faith down a new road, but it leads to even more twists and turns and dead ends. Will she be able to motor through and finally turn the page on this mystery before it's too late?