In August 1947, after India sought independence from Britishers, the Last Viceroy of India, Lord Mountbatten gave Sir Cyril Radcliffe, the responsibility of partioning India into two parts - India & Pakistan. Sir Cyril Radcliffe drew two lines - one in Punjab & another one in Bengal. The line was called Radcliffe Line.
Begum Jaan (Vidya Balan) is a prostitute who runs a brothel, out of cities, between Sakkergarh & Dorangla. She has brought up the girls, who were either abandoned, or were not accepted by their families, & now they work under her. In her brothel, also resides, an old lady Amma (Ila Arun), Sujeet (Pitobash Tripathy) , a local worker who brings her customers, & Uncle Salim (Sumit Nijhawan), a gunman who guards them. Government officers, Hari Prasad (Ashish Vidyarthi) and Iliyas Khan (Rajit Kapoor) along with Inspector Shyam Singh (Rajesh Sharma) visit her and hold her eviction notice & ask all of them to leave the brothel. Since the famous Radcliffe Line would pass between her brothel (house).
However, after various attempts when she does not agree to leave, Hari & Iliyas hire Kabir (Chunky Pandey), a famous killer of Sonapur Village to threaten her to leave. Kabir kills Begum's Son-like Dogs, Shekhu & Bhaloo, which enrages them. Next he kills Sujith when he has gone to market to bring amenities. Seeing all this, Begum asks Salim to train every girl in using arms so that they can fightback.
What happens then, do Begun Jaan and her girls survive, or are they overpowered in the ensuing battle is what forms the rest of the story.