Those who like their mysteries garnished with a large dollop of quirkiness will welcome the return of gaming maven and detective wannabe Dahlia Moss (after 2015s The Unfortunate Decisions of Dahlia Moss). In her second lighthearted adventure, the geeky girl attends a computer games convention in St. Louis as the result of a request from the mysterious Doctor XXX, who follows Dahlia on Twitch. She assumes he wants to hire her for her detecting skills, but fears he might be a stalker. At the convention hotel, she finds a dead body in one room and, in another, a nearly nude man handcuffed to a chair. From these she draws a number of conclusionsall wrong. News of the murder scares off some competitors, allowing Dahlia and her partner to advance in the games. She gets some assistance from her roommates boyfriend, whos busy practicing his Australian accent. Readers should be prepared for lengthy, plot-slowing passages devoted to what can charitably be called Dahlias thought processes. (Mar.)