Monday's child is fair of face, at least when she's the Classic Agency's model-on-the-make, Rena Varmont. But it's emphatically un- fair when Rena's found dead with her prospective roommate's address and phone number on a scrap of paper, and New York Homicide descends on that address--the West Side apartment of the roommate's uncle, retired history prof Horace Livsey. What has bemused ``Horsey'' (as his niece, struggling actress Ginny Karr, calls him) to do with Rena Varmont? Nothing--except that his scintillating, rapacious ex-wife, Zoe, the Countess Sirelli, is a major player in New York's fashion scene. It's through her that farm-fresh Ginny and her uncle get entangled with such specimens as designer Jean-Claude Franchard and Celeste Lanier, hungry editor-designate of Elegant. But Horsey and Ginny, who's being tentatively romanced by trainee-prosecutor Mark Franklin, are assured of major-player status anyway the moment Franchard's deliveryman, Paco Navarez (about to be arrested as the police suspect), drops off, at Rena's final request, a portfolio of her pictures taken by Horsey's old acquaintance Axel Gruen, a photographer who's headed for trouble himself. Innuendo aside (what does Rena's murder have to do with the fatal car crash of Classic model Diane Chaumet five years ago?), Elward (Ask for Nothing More, 1984, etc.) provides precious little action before the big leather- fashion finale (``Women's clothes and men's whips''): It's not till afterwards that the real dirt starts to come out. As appealingly amateurish as Mark Franklin--all those dazzling last-minute revelations--but not quite ready for the big time.