While traveling by ship to a convention in Copenhagen, the reluctant Professor Michael Armstrong is pressed by his fiancée and assistant, Sarah Sherman, to discuss a possible schedule to their marriage. Later in the Hotel D' Angleterre, Sarah sees Armstrong receiving a plane ticket and he explains that he needs to go to Stockholm. However, the snoopy Sarah discovers that he is indeed flying to East Berlin with Professor Karl Manfred who is also attending the convention, so she decides to follow him.