Petworth arrives at an east European country on a lecture tour. He has travelled the world on such tours, and expects an uneventful visit. But this country is in turmoil - the day after his arrival the language is changed; some of his lectures are cancelled, and parts of the country are sealed off. The people he meets are all nervous, trying to predict who will be in power next. The British Embassy staff live in a world of their own, jealously watching each other. Petworth must decide who he can trust.