Manhattan's Patience McKenna, the often-amusing narrator of this mystery debut, is tail (6'), 30, single (with a selfish lawyer-boyfriend), and a writer--sometimes of magazine articles, sometimes of pseudonymous paperback ""category romances."" And things get wildly hectic for Patience during the Third Annual Conference of Romance Writers. First there's the funeral of Myrra Agenworth, America's answer to Barbara Cartland--killed, supposedly, by a street mugger. Then Patience comes home to find her apartment the site of a locked-room mystery: inside is the stabbed-to-death body of literary agent Julie Simms. Top suspect? Poor Patience herself--who is soon doing a little sleuthing, with clues leading to the secret lives (lesbianism, prostitution) of famous romance writers. Is blackmail, then, at the root of the murder-mysteries? So it seems at first. But after yet another murder Patience arrives at a more businesslike solution, with an implausibly motivated multi-murderer. An amateurish mess of a plot, more chaotic than complex--but Patience is likably wry company, offering a few very funny lines. . . and more than a few convincing, satiric close-ups of the Category Romance biz.