بلبل سرگشته

A widowed father remarries; the stepmother desires his son, drives the father to kill him and boils the boy's head in a pot. The daughter, helped by her brother's spirit, which has become a wandering nightingale, exposes the stepmother; in his rage the father kills her and then dies himself, and the daughter renounces marriage and turns to mystical thought. According to Persian Wikipedia, the play is based on an old Iranian folk tale, won first prize in the first Fine Arts playwriting competition in 1956, and was staged several times in Tehran from 1958, including at the Sangelaj hall.