When a library fire serves as a cover for a brazen art theft, teenage detective Kay Tracey plunges into a dangerous investigation involving a mysterious cult. Kay must navigate the social pressures of Carmont High School while tracking elusive suspects and evading the sabotage of her jealous classmate, Ethel Eaton. Supported by the Worth twins, Betty and Wilma, Kay utilizes her observational skills to uncover the truth behind the firebug menacing Brantwood. The narrative follows a traditional mystery framework, emphasizing Kay's deductive reasoning and her ability to maintain focus despite external threats and personal rivalries.

This work represents a classic entry in the long-running Kay Tracey series, reflecting the conventions of mid-twentieth-century juvenile detective fiction. The narrative relies on a formulaic structure that prioritizes the protagonist's agency and her ability to outsmart both criminal elements and social peers. Readers often engage with these stories for their nostalgic tone and the straightforward, puzzle-oriented nature of the central mystery. The text functions as a character-driven procedural that emphasizes the resilience of the teenage sleuth in the face of escalating danger.