 Semyon Gorbunkov, a friendly and naïve husband and a father of two goes on a world cruise. Visiting different countries and cities, him and his new friend Gennady, whom he met on the ship, have fun seeing the world. Arriving in Istanbul, Gorbunkov takes a stroll and accidentally slips and breaks his arm. Uttering a blasphemous phrase (which turns out to be a secret code intended for Gennady, a contrabandist), he is taken to a nearby "clinic", where an arm cast, being a decoy for jewellery and diamonds inside is put on his arm. Back in the USSR, Gorbunkov informs the police about his mishap...