John Streyer, a scientist who defected to East Germany 15 years earlier after participating in an espionage ring, has decided to return to the U.S. Two representatives of a nation "unfriendly to the United States" attempt to detain Streyer at John F. Kennedy International Airport but he gets away. Assistant Director Arthur Ward, already in New York on FBI business, works in the field with Erskine and Colby on the case. Ward had headed the bureau's espionage desk at the time Streyer escaped capture by defecting to East Germany. Streyer is being squeezed by the FBI, which wants to capture him, and the Eastern Bloc country, which has decided he knows too much and must be silenced.
—Bill Koenig