Intricate but entertaining page-turner about the Brits vs. the IRA, by novelist and nonfiction author Gadney (Cry Hungary!, 1986, etc.). The end of the cold war and the demise of the Eastern bloc has produced a scramble for new villains; here, the Irish Republican Army does good service in the role of menace to free society. Alan Rosslyn, a 30-ish senior investigator for Customs and Excise, is celebrating his greatest triumph--the capture of Dee McKeague (an IRA runner caught red-handed with plastic explosives and Russian- made arms)--when his life is suddenly shattered: His fiancÇe, Metropolitan police officer Mary Walker, is killed during an abortive raid on the headquarters of the counter-espionage service MI5. Apparently, she was simply in the wrong place at the wrong time (having gone to the building for a job interview). When McKeague requests to see him in jail, however, Rosslyn discovers that Mary's death may have been more than a coincidence. Soon thereafter, the prisoner dies in custody; the customs man is framed for her death; and Rosslyn finds himself embroiled in a complicated plot involving assassinations, bombings, and fugu (the Japanese blowfish whose liver contains a deadly poison). Impeding Rosslyn's investigation, meanwhile, are interagency bureaucratic rivalries and someone within MI5 who not only killed McKeague but set Rosslyn up to take the fall. Further complicating his life is the dead terrorist's sister, also an IRA member, set on revenge. Rosslyn must sort it all out, while coming to terms with the death of Mary, whose diary reveals more than he ever wanted to know. Gadney remains not only in control of his plot but demonstrates a gift for description: in all, a roller-coaster ride that carries the reader along at breakneck speed.