In June 1963, the Berlin Wall has been up for almost two years. The CIA has had a rough time maintaining an intelligence operation in East Germany, known as the German Democratic Republic (GDR), because of the Stasi — the East German secret police who have perhaps the best surveillance system ever established.

There are rumors that the Germans were working on a weapon of mass destruction during World War II that was never completed, but the US intelligence service has no easy way of finding out anything about this project. For the security of the free world, they want to beat the Soviets in acquiring what information they can.

Ted Robinson, an agent who is acquainted with financial analysts Charlie Ebersole and Liz Reid because of their operation in Castro’s Cuba, attempts to recruit them to go through the Wall into the GDR. Liz’s second cousin lives in the GDR, and his father, who is dead, may have worked on the World War II project. Motivated by patriotism and concern for Liz’s cousin, who may have some knowledge of what his father did, the pair agree to go, despite the obstacles put in the way of travelers to the GDR. Their job is to gather what information they can before the Soviets do, and stay out of the hands of the Stasi.