A severed human arm leads to an unholy web of spying, murder, and betrayal in war-torn London: a first novel from BBC-TV filmmaker Lawton. Sgt. Frederick Troy, treated with an uneasy combination of respect and suspicion because of his moneyed, foreign-born family, soon identifies the arm (some smart detective work here) as belonging to the late Bertoldt Brand, a specialist in lightweight alloys and rocketry who's evidently the latest to follow his project team-- engineer Gregor von Ranke and professor-turned-dockworker Peter Wolinski--into the peace that passeth understanding. Conservative princess Lady Diana Brack, seen leaving Wolinski's flat, leads Troy to a likely suspect: OSS Major Jimmy Wayne, who obligingly implicates himself more deeply when a copper who wedges behind his car in a London pea-souper is found dead. But the trail stops there. According to the American high command, Wayne was in a meeting with Ike and Patton at the time of this last murder, and some other dude did it. So Troy, giving his days to interrogating Brack and his nights to slipping between the insistent sheets of Sgt. Larissa Tosca, his inside contact among the Americans, goes after Wayne on his own. The result, as Troy totes it up toward the end of this beautifully paced debut: He gradually gets a sense of just what Wayne's mission in Britain is, and why his superiors would be so willing to cover for him; he gets shot twice, stabbed four times, bombed twice, and beaten up more times than he can count; and in an overextended but crucial epilogue four years later, he finds that the plots he thought he'd laid to rest were more twisted than he'd ever imagined. Gorky Park in the London Blitz. Newcomer Lawton has an urban documentarist's eye and ear for his jangled world--London has seldom seemed quite so foreign--and a nasty sense of how little slips can indeed sink ships.