In the early Turkish Republican era, that is 1930s, an engineer working in a mining company in Zonguldak moves to the city with his wife and younger sister. The people in the local community consider Seniha, the sister, as ugly, asocial and sullen. In fact, the sister has internalized this view of herself and lives an alienated social life. Events take an irreversible turn when Mukerrem, the engineer's wife, is introduced to the son of the richest and most well-known family in Zonguldak, Nuzhet during a republican ball. He is young and handsome, but also spoiled and known as a Casanova in the small community. Even the much older women are ready to be his lover. Halit, the husband, has a distant relationship with both his wife and his sister. Over time, Mukerrem and Nuzhet are involved in an affair, and they secretly meet on different occasions, but she demands to be more than a mistress. The affair would eventually end in Nuzhet's death at the hands of the husband after he is informed by his sister about their extra-marital escapade. It turns out that Seniha, the person who seems to see herself as a hopeless case, has snitched to her brother about it out of jealousy. What is more, she conceals certain information during the interrogation that could reduce the punishment that her older brother is to get. Having lost both her husband - in jail - and her lover - dead - unexpectedly and being hearth-broken by Seniha's cold-blooded accusations and actions, Mukerrem flees to Istanbul. In less than a decade, the husband is released, and he meets his sister at her request. However, he is still enraged with his sister.