Faintly diverting, uncertainly paced gal-reporter suspense--as Muriel Axelrod, secretary at Lovell Munitions in San Francisco, works undercover for a Washington foundation ""headed by Jack Anderson."" The mission: to find solid evidence about Lovell's illegal arms sales to South Africa and other forbidden customers--sales which have been receiving secret support from the US State Department. Muriel gets some dubious help along the way from COCOA, a group of activists for office-worker rights. She gets spied on by a corporate thug--who pretends to share the model-railroad mania of Muriel's gay roommate. But eventually, despite a devilish attack from the bad-guys (they tamper with the microwaves in her video-display terminal), Muriel follows the illegal-arms trail to Mexico. . . where she's saved from assassins by Lourdes Pagano, the homesick, vengeful Argentinian wife of one of the villainous Lovell executives. First-novelist Biederman doesn't quite have the craft to manage this coincidence-triggered plot twist--which also involves Muriel's oily lawyer-brother Bernie (who just happens to be the attorney for Lourdes' stepson). The slight action is all bunched up at the end; there's little suspense and no mystery. But, pleasantly padded out with Muriel's passion for old movies, this shakily plotted debut is breezily agreeable much of the time--with some promise of better capers ahead if Biederman can find a tight storyline to go along with her nice feel for character-comedy.