Kiranjit Ahluwalia (Aishwarya Rai), a battered Punjabi people|Punjabi homemaker and mother of two, living in Southall, UK with her 2 children and abusive, alcoholic husband, Deepak Ahluwalia (Naveen Andrews). Unable to bear the brutality and repeated rapes at the hands of her spouse, she sets fire to his feet, unintentionally killing him. Charged with murder, her case comes to the notice of a group of South Asian social workers running an under funded organization called the Southall Black Sisters.
After being sentenced to life imprisonment, she befriends her cellmate, a caucasian woman named Veronica Scott (Miranda Richardson), who teaches her English language|English. Veronica is also friends with several girls in the prison and stands up for Kiranjit against the local prison bully. Veronica realises what a good person Kiranjit is and enlists her brother, Edward Foster QC (Robbie Coltrane), a highly respected Queen's Counsel, to aide in Kiranjit's appeal. Edward, in turn, realizes Kiranjit's importance to his sister and the importance of her case. His sister's request has additional meaning given that Veronica would not let him help her with her own appeal due to their on off relationship since childhood.
Before Kiranjit's appeal hearing the Southall Black Sisters bring her plight to the attention of the media by organizing rallies to gather public support for her freedom. She is ultimately freed by the judicial system in a landmark case called "R v Ahluwalia", redefining ''Provocation (legal)|provocation'' in cases of battered women in the UK. (She was reconvicted from murder to manslaughter; but released with time served). Kiranjit is reunited with her children and subsequently given an award by Cherie Blair, for her crusade against domestic violence. (The award is not shown on the film although it is accredited at the end).