When Floyd Macklin, an American black marketeer, escapes from a Black Maria, he vows to kill prosecutor Hans Eckert and Major Caldwell, the men responsible for his 20-year sentence. Jake sets up a meeting with Macklin at the Prater Amusement Park, but Caldwell and Lt. Hoffman arrive with the Viennese police before Jake can capture his man. Macklin rushes away and Jake is jailed as a suspect in engineering Macklin's original escape.

Jake Webster is startled to meet in Vienna Charley Stokes, whom he saw killed on a beach in Albania after the pair had blown up a power installation. Charley explains that, though seriously wounded, he was saved by Elga Compani, number two official in the Albanian Secret Police and is now married to Charley. Jake begins to suspect that Charley and Elga are still loyal communists.