Wealthy socialite Elizabeth Cateman Kingsley has hired Helen to find a missing John Singer Sargent painting, owned by her late father. After his death, many of Davis Kingsley's books were donated to the Flora Park Library, and his daughter suspects the small watercolor--worth a million dollars--was tucked away inside one of those dusty tomes.

To search the stacks, Helen applies for a job as a library volunteer and discovers the library has a catalog of complaints--from a mischievous calico cat to the mysterious disappearance of various items that some of the staff are attributing to a ghost. Things only get worse when a dead body turns up in a parking lot. Now Helen is bound and determined to find the killer as well as the painting--before she's taken out of circulation herself.