Begum Jaan (Vidya Balan) is a prostitute who runs a brothel between the cities of Sakkergarh & Dorangla. The prostitutes are a number of girls she raised herself, who were either abandoned or disowned by their families and now work for her. The members of the brothel also include an elderly woman known as Amma (Ila Arun), Sujeet (Pitobash Tripathy), a local worker who brings her customers, and Uncle Salim (Sumit Nijhawan), a gunman who guards them.

They are pestered by government officers Hari Prasad (Ashish Vidyarthi), Iliyas Khan (Rajit Kapoor), and Inspector Shyam Singh (Rajesh Sharma) who visit her and ask all of the residents to evict the brothel, as it lies on the land that the Radcliffe Line is to pass through. After several failed attempts to convince Begum Jaan and her band to leave, Hari and Iliyas enlist the help of Kabir (Chunky Pandey), an infamous killer in Sonapur, to threaten her to vacate the brothel. Kabir proceeds to kill Begum's beloved dogs. He then he kills Sujeet while he is running errands, enraging them further. As a result of Kabir's intimidation tactics, Begum asks Salim to train every one of her girls to use weapons and fight back.

Meanwhile, Master Ji (Vivek Mushran), Laadli's teacher, is in love with Begum Jaan & proposes to her, unaware that another prostitute named Gulaabo (Pallavi Sharda) , harbors feelings for him as well. Begum Jaan rejects his proposal and asks him to leave, leading an irate Master to concoct a plan to kill her. He convinces Gulaabo to run away from the brothel, betraying Begum Jaan. Gulaabo later slits his throat, but ends up being shot dead soon after.

That same night, Kabir and his men attack the brothel, as Begum and the girls fight back but to no avail. The men throw fire javelins inside the brothel, causing the building to be engulfed in flames. Begum Jaan and her girls smile while looking at their home being set ablaze; they walk inside the building and shut the doors. They burn to death as Amma narrates the story of Rani Padmavati of Chittorgarh, who refused to fall into the hands of the enemy, and instead martyred herself and died a valiant death, not unlike the plight of Begum Jaan. Towards the end, their guilt for their actions take a toll on them, so bad, that Illias commits suicide. That is when the end of Begum Jaan’s legacy is shown, symbolized by the ashes of the brothel.