Concentration-camp survivor Hugo Hartman is a double agent--not a double-crossing operative, just a topnotch freelancer who happens to work (never simultaneously) for both the CIA and the KGB. But now Hugo's wife Gerda has finally died in Connecticut after years of childlike catatonia in psychiatrist son David's asylum (a condition brought on by memories of her life-saving dishonor as mistress of the death-camp commandant); and Hugo wants to quit spying and settle down with Vienna antique-shop owner Rebecca. Neither the KGB nor the CIA wants to let Hugo go, however, and he's in a fix. So, while in N.Y. on KGB assignment (determining whether a UN attache is a traitor), Hugo follows up a leftover clue from a previous, failed CIA operation, hoping to find something with which he can bargain for his freedom--and what does this sleuthing lead him to? Klaus Reinhart, the death-camp commandant who ruined Gerda's life, now a night-clerk in a Manhattan flophouse. A perfect opportunity for revenge-plus-escape: hitherto-cowardly Hugo will kill Klaus and use the body to fake his own hotel-window-jump suicide. . . which he does, while both the CIA and KGB are catching on to his duplicity. A crisp, tidy, central plot--with an appealing semi-hero (Hugo is loathed by cruel son David for his cowardice) and leanly effective supporting characters (a KGB chief who collects jazz records, a CIA official being badgered by his superior). Unfortunately, however, Winchester (a pseudonym) winds up bungling the narrative tightness here--with a last-chapter twist that's less than convincing, with an apparently crucial subplot (the failed CIA mission and its relevance to the KGB chief) that's never developed. And little details (like the implausible history of wife Gerda's disease) trip him up. Not first-rank, then, but a mostly-satisfying, fast-reading little treat--with some hints that Hugo (who winds up back in KGB harness) may return for future, welcome exploits.