Farah is consoled by her friend Poppy after breaking up with Asif, a married man with whom she has been having an affair. Farah learns that Asif's marriage to Maryam was never registered in England, and that Farah has Maryam's permission to marry Asif and become his second wife. At the wedding, Farah tells Poppy that Maryam and Asif have not slept together in years. Maryam overhears this. Farah moves in with Asif and Maryam, their two children and Asif's mother, Sabia.
Asif picks Farah up from work. Believing that he is taking her out to dinner, she is disappointed when Asif explains that he would prefer to eat at home. On her way to the bathroom at night to get some water, Farah notices that Maryam is not in her bed. As she is about to turn the knob on Asif's door, she hears laughter coming from inside. She meets Asif in the bathroom and accuses him of sleeping with Maryam. He assures her that they were only chatting.
Maryam returns home from work and is ignored by Sabia. When Maryam arrives home, she notices that Farah is looking tired and offers her a spoonful of a tonic which she believes has re-energizing qualities. On a shopping trip, Farah tells Poppy she has stopped taking the pill in order to get pregnant. Her rationalisation is that the birth of a baby boy will prevent Asif from leaving her. At home, Asif tells Farah that her mother has been in an accident. She later dies in hospital.
On Christmas Day, Asif gives each of his wives one half of a diamond ring. After dinner, Maryam and Farah argue over their competing affections for Asif. That evening, Farah's father tells his daughter of his intention to return to Pakistan. Farah argues with Asif over his refusal to take her with him to Pakistan on his business trip and the fact that he may be away for up to three months. Farah raises the subject of having a baby of their own and moving out of the house. Asif promises to think about it while he is away.
That night, Farah gets up to answer a knock at her bedroom door, finds no one there, and discovers a box outside containing some powder and a card saying "For good health, Sabia". Farah pours the powder into her flowerpot. The next morning, she discovers that the flowers have died and runs to find Asif, who is about to leave for the airport. She explains that she thinks Sabia tried to poison her and makes him promise that they will move out on his return. After Asif's departure, Maryam and Farah agree to be friends.
At a dinner party, Maryam boasts of her ability to sexually satisfy a man. Farah overhears and gets angry. At work, Farah discovers that a woman has entered her workplace and has been asking questions. Farah tries in vain to find her.
Asif gets back from Pakistan and tells Farah that he has decided not to leave Maryam. Farah takes Poppy's advice to leave Asif and packs her bags. On her way out, she vomits. Discovering she is pregnant, Farah stays in the house.
Maryam starts a job, while Farah spends her time convalescing in bed, making notes in her calendar of the start and finish times of Asif and Maryam's love-making sessions. Farah miscarries.
Farah visits Bibiji, a 103 year-old healer who has a reputation as a miracle-maker. Farah leaves with a packet of powder. Maryam becomes ill. While at Maryam's bedside, Farah hears a voice in her head telling her not to put the powder in Maryam's glass of water and refrains.
Coldly labeled by Asif as "the madwoman in the attic", Farah introduces herself to Asif's colleagues as his "second wife" and slips the drug into the carafe of water in Maryam's room. Farah comes across a doctor's letter addressed to Maryam confirming her pregnancy. In the middle of the night, Sabia and Farah are awoken by Maryam's screams. They discover Asif lying in bed, dead.
