At the start of this quirky series launch from Towles (The Ridders), an L.A. PI, Mari E, meets a prospective future partner, ex-LAPD detective Derek Abernathy. Mari asks for his help looking into the extortion of Conrad McClaren, a federal appellate judge in San Francisco. McClaren has received two notes from an anonymous blackmailer, and though Mari has just begun to look into the matter, not even knowing the basis for the blackmail, she herself has gotten warning messages delivered to her home advising her to stop her inquiries. That case may be connected to one Abernathy has been handling focused on the strangling murder of art student Sasha Michaud and the related disappearance of female journalist Elise Turner. Turner’s protégé, Nina Richmond, has also been found dead, killed in the same way as Michaud. Mari and Abernathy team up, and Towles gradually reveals pieces of Mari’s complex backstory, which includes posing as an art gallery owner to conceal her profession from her family. The page-turning twists keep coming as do welcome doses of humor. Fans of bantering sleuth duos will be eager for the next book. (Self-published)