Cate Fante, a rookie Philadelphia judge and the eponymous Dirty Blonde in Lisa Scottoline’s implausible new thriller, has a secret compulsion for picking up guys in sleazy bars — until she’s exposed after ruling against a desperate-to-make-it-big lawyer, Richard Marz, who claimed Hollywood producer Art Simone stole his idea for a hit legal TV show. Both men turn up dead, and Fante learns that Simone had produced a soon-to-be-aired spin-off, starring a sexy judge with a secret sex life. Meanwhile, someone involved in the case is bent on destroying Fante’s career. Whew! Mercifully, all the unlikely plot contortions are mitigated by Scottoline’s assured way with dialogue and her ability to render character in a few swift strokes.