KGB officer Anatoli Petrov defected to Britain two years ago--but now, in the midst of his long debriefing, he has suddenly clammed up. What has frightened him? That's the puzzle for SIS agent James Lawler, who is assigned to befriend Petrov, takes him (and sexy girlfriend Siobhan) on a holiday trip, and learns some of the answer: Petrov, referring to the case of George Blake (a captured mole who was supposedly killed after debriefing), explains that he's afraid of a post-debriefing execution. So Lawler starts looking into the Blake case; he wonders why he's being trailed by an ex-SIS agent; he tries to win Petrov over by helping his ex-wife, an outspoken Pole, to defect from East Berlin. And, as this defection excursion gets underway, the familiar layers of espionage secrets--double-agents, moles in SIS--start to unpeel. Like other recent Allbeurys: a minor mini-Le CarrÃ‰--but well-knit, urbane, with likable lead characters (Lawler suffers throughout because the courts won't allow him to raise his abused illegitimate daughter) and a neatly fitted spy-maze.