In what Christopher Lehmann-Haupt of The New York Times called "the plot of plots," Robert Littell has created the CIA "legends" Francis and Carroll, dubbed "The Sisters Death and Night" by their cohorts. But few know what these enigmatic and extremely dangerous operatives do. They plot-and they're plotting the perfect crime. They've located the perfect pawn-the Potter, the exiled ex-head of the KGB sleeper school-and, with artful deception, the Sisters...