Complex, brisk, hop-plotted mirror games--as the Russian military underground deploys its powers for a brand new Revolution in post-Brezhnev Moscow. The new First Secretary of the Communist Party is short, fat Khamovkhin, and he's sweating in his shoes when he gradually discovers the enormity of the plot threatening him with overthrow--and assassination. British intelligence also is aware that something unthinkable is underway: some infrared satellite photos have revealed that an entire Finnish village near the Soviet border has been emptied of its population, that an unannounced invasion of Finalnd is in motion. So the Brits fly in Folley, a whitesuited ""falcon,"" by night helicopter to see what's happening. Folley does indeed find a hidden regiment of Soviet tanks, but he's captured, tortured, and whisked off to Leningrad while two more falcons are flown in: unlikely deskmen--comic types. Meanwhile, Vorontsyev, top young man in the Special Investigations Department (KGB), is figuring out the Big Revolutionary Plot: the militaristic Old Guard has formed a secret group to invade Finland, thus blowing up Khamovkhin's signing of a SALT III agreement. And they are being led by the mysterious Kutuzov, who happens to be Vorontsyev's very own stepfather, General Gorochenko, a hero of the original Leninist group who has survived through every change of power and hopes to bring Communism into full flower. So--an enormously involved tale that gets heat from its sheer briskness; but thoughtful espionage readers may find it all a bit thin despite the heavy, stone-gray exoticism of the Russian locales. Ambitious, solid--just not quite top-drawer.