With a troubled past and a job that attracts too much attention from the law, private investigator John March has always been the black sheep of his merchant banking family—which makes the identity of his latest client all the more surprising: his smug older brother. David March has been having affairs with anonymous women he meets on the internet, and now one of these women is stalking him. David knows her only as Wren. She, however, knows everything about David—and she's threatening to tell his wife and colleagues, ruining his life. But after Wren turns up dead, John finds he's no longer searching for a stalker—now he's looking for a murderer, and the clues keep leading him back to his older brother's doorstep.