A rookie Secret Service agent's troubles are only beginning when a scheming senator gets killed on her watch--in this fleet political thriller from Shelby, the Los Angeles-based author of This Far From Paradise (1988). Even if she'd followed the safety precautions she let Senator Charles Westbourne fatally tone down, Holland Tylo, left fatherless herself by an assassination 15 years ago, would have been no match for the hired killer who calls himself Preacher--a man with no nerves, years of experience, the best connections in the business, and a real fondness for his work. The true test of Holland's mettle comes after she's shuffled onto enforced leave and realizes she's carrying something--a diskette full of damning testimony against all the best senators--that Westbourne's killer missed. Everybody wants the diskette, and Preacher, coolly eager to kill Holland and grab the goods, will have to queue up with Holland's boss, Secret Service deputy director Arliss Johnson; her lover, Service agent Frank Suress; and madly ambitious Senator James Croft, determined to buy his way into the Cardinals, Westbourne's senatorial cabal, with the diskette's dirty linen--or use it to vault over the Cardinals into the White House. From here on in, you could probably write the story yourself: Holland goes on the run, calls people who assure her they can bring her in safely, gets betrayed, and goes on the run again, as Preacher, carefully established as a sexual sadist in addition to his other habits, strides a step behind her, repeatedly just missing her while winnowing the field of the less fortunate. But you could never write it as rapidly and efficiently as Shelby, whose narrative instincts, honed presumably by bigticket movies, carry even the most preposterous counterplots into a current so dizzying that you'll probably finish the book in less time than it would take to see the movie. An even slicker version of The Pelican Brief, with the Senate sitting in for the Supreme Court. Paging Julia Roberts.