Kathleen is busy running the library and planning her upcoming wedding to detective Marcus Gordon, when she suddenly stumbles across a body in the library. She is surprised to learn that the deceased was in the middle of an unlikely heist--it seems like he was trying to steal one of the paintings that had been in a box in the library's workroom. Kathleen never knew any of the library's rotating artwork was valuable and can't imagine what the dead man wanted with it.

But then an art history expert called in by the police identifies the almost-purloined painting as a piece that might have been part of a previous high profile art theft. Owen's and Hercules's whiskers are already twitching, and events soon make Kathleen realize that whoever killed the wannabe art thief has more than murder on their mind. Kathleen and her clever cats will have to work fast to prevent anyone else from getting hurt.