It is early December, 1929. Cyrus Skeen has concluded his case in The Chameleon, in which he uncovered a cell of the Nazi Party near Stanford University in Palo Alto, a college town south of San Francisco. But into his life come two Germans, one a Hollywood director, another an operative of a Marxist "think tank" in the midst of relocating from Germany, which is becoming more hostile to Communists and other fellow travelers. They are twin brothers and both wind up dead early on in the case. One is supposed to have murdered the other, and attacked Clara Reyes, Skeen's loyal and resourceful secretary. The German Consulate in San Francisco, with which Skeen has crossed swords in the past during the Esterhazy case earlier in the year, avers that neither man was what he seemed to be.