Brennan (Loose Lips) impresses with this atmospheric whodunit set against the backdrop of Jack the Ripper’s killing spree in 1888 London. Rather than the mean streets of Whitechapel, however, Brennan focuses on “the golden age of the gentleman’s club,” the most notorious of which is Sizar’s, an establishment whose members are “soilingly, ruinously ungentlemanly” in their sexual proclivities. Stewart Marsh, who scouts young men willing to have sex with Sizar’s members, is on holiday in Brighton when he stumbles on the drowned corpse of London escort Marty Piper. Marsh’s gruesome find soon comes to the attention of Det. Insp. Oscar Glass, who investigates London’s gentleman’s clubs for criminal activity. While Glass struggles to narrow the list of suspects—Piper accrued plenty of enemies as a “boy-whoring master villain”—he’s handed a second, possibly connected murder to solve. Brennan’s reveals, when they come, are plenty shocking, but the narrative’s main strength is its vivid portrayal of a segment of Victorian society rarely depicted in mysteries. This illuminates a dark corner of British history, with grimly satisfying results. (Self-published)