A young Bangladeshi woman, Nazneem, arrives in 1980s London, leaving behind her beloved sister and home, for an arranged marriage and a new life. Trapped within the four walls of her flat in East London, and in a loveless marriage with the middle aged Chanu, she fears her soul is quietly dying. Her sister Hasina, meanwhile, through letters to Nazneed, tells of her carefree life back in Bangladesh, stumbling from one adventure to the next. Nazneen struggles to accept her lifestyle, and keeps her head down in spite of life's blows, but she soon discovers that life cannot be avoided - and is forced to confront it the day that the hotheaded young Karim comes knocking at her door.
After her mother kills herself, 17-year old Bangladesh-based Nazneen gets married to 42-year old Chanu Ahmed, and re-locates to live in Britain circa 1980, leaving her dad and sister, Hasina, behind. She soon gives birth to two daughters, Rukshana and Bibi. When her husband loses his job, she takes up sewing and meets with Karim, who supplies her dress material, and both get attracted to each other. While racism prevails in the community, especially from white supremacists groups, it escalates after the events of September 11, 2001, compelling a debit-ridden Chanu to consider re-locating back to Dhaka, much to the chagrin of Rukshana. While the thought of being reunited with a seemingly care-free Hasina attracts her, Nazneen must now chose between living in their apartment on Brick Lane, continuing her affair or even getting married to Karim, or accompanying her husband back home.