 Istvan Sladek, an agent for a Communist Eastern European nation who is operating in the U.S., has obtained a coded list of opposition leaders in his country. But in getting the list, he fatally shot the editor of a newspaper for Slavic Americans. Erkine and Rhodes lead the FBI s hunt for Sladek. At the same time, Sladek knows agents of his country will liquidate him the moment Sladek gives up the list. Complicating all of this is the fact Sladek, during the preceding six months, fell in love with a woman who immigrated from his country. The woman is torn whether to help Sladek or help the FBI.