When a homeless man is found dead in Golden Gate Park, Inspector Kate Martinelli must navigate the cryptic testimony of a witness who speaks only in quotations to solve a homicide. Kate and her partner, Al Hawkin, face the challenge of investigating a victim with no identity and a community of witnesses who distrust law enforcement. The narrative follows Kate as she attempts to decipher the motives of Brother Erasmus, a man who embodies the archetype of the Fool. As the investigation progresses, Kate uncovers links to a defunct cult and a history of vengeance that complicates the case, forcing her to look beyond the surface of the city's marginalized population.

This novel is characterized by its focus on the intellectual friction between a pragmatic police officer and a witness who refuses to engage in conventional dialogue. The narrative structure relies heavily on the tension created by the protagonist's struggle to interpret the cryptic, quotation-based speech of Brother Erasmus. Readers often note the author's ability to balance the gritty reality of a police procedural with deeper, thematic inquiries into spirituality and the nature of the 'Fool' archetype. The setting of San Francisco serves as more than a backdrop, acting as a complex environment that shapes the motivations of the characters involved in the investigation. The work is generally regarded as a thoughtful entry in the series that prioritizes character development and thematic depth over simple action-oriented tropes.