Karel Cernik (Fredric March) is the leader of a Czechoslovakian circus troupe. When the country falls under Communist rule, the proud and independent Cernik finds that he is no longer free to operate his circus as he sees fit. Many of his performers are conscripted into military service, and his equipment and possessions are declared government property. Aside from the politics, he has his daughter's romance with the handsome but unreliable lion tamer to deal with. Finally, when Cernik's remaining performers are ordered to insert pro-Communist messages into their acts, he decides that he can take no more. He hatches a plan. But is there a Communist spy in the circus?