Rostworowski received rave reviews for his tragedy Niespodzianka (Surprise, 1928–1929), about parents murdering for money their own son, who had emigrated to America and returned to visit them. The work was staged at the Juliusz Słowacki Theatre in 1929, and in 1932 won the national book prize. Niespodzianka was regarded as Rostworowski's most notable achievement by the Polish Nobel laureate Czesław Miłosz. The novel tells an old story, first recorded around the 17th century. A peasant family in financial despair is visited by a well-dressed man asking for lodgings. They kill him in his sleep to steal his belongings, but subsequently discover that he was their own son. Both parents suffer psychologically, and the money is given to their younger son to pay for his education. The story was staged by director Jan Świderski in Poznań in 1987.
