Kazem the middle-aged highly respected foreman of a factory falls in love with Zahra, the young daughter of one of his workers and marries her. From his previous marriage, failed because of his ex-wife's unfaithfulness, he has two sons, Aziz and Ja'far. Ja'far, who is in fact the result of his mother's liaison and therefore despised by his father, finds the occasion ripe for his vindictive plan against Kazem and Aziz. Taking advantage of Kazem's suspicious character, Ja'far suggests that something illicit is going on between his new wife and his son. In his conspiracy, Ja'far is assisted by Karim, the obtuse worker who is desiring Zahra and therefore holds a grudge against Kazem