Satya Chaudhry, a woman dying of cancer, requests her childhood acquaintance, Roop, to provide companionship to her husband, Dev. Roop agrees on the condition that she marry Dev. Once married, Dev tells Roop that their relationship will be cordial and platonic. A depressed Roop takes solace in music, which she begins learning from the madam of a brothel, Bahaar Begum. She also begins working in her husband's publishing house. Roop expresses interest in writing about the condition of the locality in which the brothel is located, during which she interacts with a womanizing blacksmith named Zafar.
Zafar wants to exact revenge on his parents, Bahaar Begum and Balraj Chaudhry (who abandoned Zafar after Balraj ended his extramarital affair with Bahaar) by seducing Roop, as she is married to Balraj's legitimate son, Dev. Roop misconstrues Zafar's intentions and falls in love with him. She also begins to develop a friendship with Dev, to Satya's pleasure. Satya dies after urging Dev to give Roop a chance and to forgive Balraj for his affair. In another effort to humiliate Balraj, Zafar instigates communal hatred in his friend, Abdul, by demanding for the partition of India on religious lines, which Balraj and Dev do not support.
When Balraj becomes aware of Roop and Zafar's affair, he confronts Bahaar Begum and Zafar. Bahaar, who disagrees with Zafar's approach, warns Roop. Heartbroken, Roop consummates her marriage with Dev, but insists that she would never be able to love him. As Abdul Khan's political stance gains leverage, riots against Hindus and Sikhs in the city take place, during which the Chaudhrys decide to flee to Amritsar with the help of Zafar, but not before Saroj, the benevolent maid, is brutally stabbed to death. He confides in Roop that he eventually fell in love with her, despite his early intention. While boarding a train, Zafar is murdered by Abdul, as Roop and Dev escape. Ten years later, Roop and Dev, still in a loveless marriage, are interviewed about their experience by Aditya, a journalist documenting the partition.