Three men meet on the outskirts of London to hatch a plan to steal the wealth of a nation in this thriller by an Edgar Award-winning author.   They are three ordinary-seeming men--one fat, one tall, one thin. But their goal is anything but ordinary, and they have no regard for the chaos and horror that will be unleashed in the process. Once their plan is put into action, the death toll will rise and rise . . .   It is up to Department Z's Gordon Craigie to put a stop to these powerful and ruthless men. His only clue is a mysterious diamond-shaped card. It is on this small lead that the fate of Department Z--the ace detectives within British intelligence--hinges. But with the life of Craigie's top agent Toby Arran now on the line, this one clue may not be enough.