Anti-Nazi tract laced with 1938 newsreel footage finds American girl (Bennett) married to a German (Lederer) gradually learning he is a Nazi, trying to get their son to America.

In July 1938, The Smart World magazine art critic Carol Hoffman prepares to leave New York with her husband Eric on a trip to Germany. Eric must go to Germany to help his father with the family business, but both he and Carol see the trip as an extended vacation. Dr. Hugo Gerhardt arrives at Carol's office to ask a favor. His brother, the renowned philosopher Hans Gerhardt of Berlin University, has been taken to the Dachau concentration camp. Hugo has raised $500 in bribe money and asks Carol and Eric to deliver it for him. Arriving by boat in Bremerhaven, Eric tells Carol he feels like a tourist, not a native. On the train to Berlin, Eric reads a German newspaper to Carol, telling her how, according to the journal, there is no unemployment in Germany and how German radios and cars are cheaper, yet superior, to their American counterparts. Seeing a train of prisoners, Eric and Carol are informed by a fellow traveler that they are Austrian forced labor. The traveler also comments on how inferior German products really are. At the Berlin train station, the couple is met by Freda Heinkel, Eric's old flame. Once at home, Eric's father Heinrich explains that the old Germany he knew is gone and that Eric must now either take over the family business or sell it. At a large military rally, Eric begins to feel that Germany is "alive, exciting," much to Carol's chagrin. Then, at a dance, Eric confesses to Carol that he wants to stay in Germany and run the family factory. Freda arrives and tells Carol that they cannot give the money to Hans Gerhardt, as he is a traitor to his country. Carol, despite this, vows to deliver the money as promised. At the Overseas News Service , Carol meets American reporter Kenneth Delane. When Carol asks about Hans, Ken tells her that Gerhardt died in Dachau of "acute appendicitis." Ken suggest that Carol give the money to Gerhardt's family. On the way to see the Gerhardts, Carol and Ken run into a Storm Trooper patrol, which is making Czech women and children pick up garbage in the streets. At the Gerhardt home, Frau Gerhardt thanks Ken and Carol, but refuses their offer to send her to America. When told the official cause of her husband's death, Frau Gerhardt informs them that Hans had his appendix removed twenty years earlier. After Carol returns home, Eric dismisses what she has seen as isolated incidents. When he informs Carol that he is having dinner with Freda and some Nazi officials, Carol calls Hitler "Schickelgruber" (his real name), a comment that Eric declares is grounds for divorce. That night, Carol attempts to help their neighbor Friehof hide his eldest son, who has just escaped from a concentration camp. When the Gestapo arrives, however, Friehof's youngest son turns them in. At Gestapo headquarters, Carol is interrogated by Herr Deckart, but Ken, using the power of the American press, gets her released. At Hitler's speech at the Berlin Sportspalast, Eric fully absorbs the Nazi idea, to Carol's horror. The next morning, Eric reveals to Carol that he has decided to stay in Germany permanently. When Carol protests, Eric admits that he has joined the Nazi party and is in love with Freda. Carol agrees to a divorce, but Eric refuses to let her take their son Ricky back to America with her. Ken offers his help in sneaking Ricky out of Germany, but Eric foils the plan. Heinrich confronts his son, however, telling him that the boy belongs with his mother. When Eric, with Freda's support, still refuses to give up Ricky, Heinrich tells him that his mother was Jewish. Repulsed, Freda leaves and Heinrich informs the shattered Eric that now he will have to suffer what he would have done to others. At the train station, Carol and Ricky leave Germany, as Ken tells them that he will be staying in Germany for the duration.