Kahaani (; ) is a 2012 Indian Hindi-language thriller film co-written, co-produced, and directed by Sujoy Ghosh. It stars Vidya Balan as Vidya Bagchi, a pregnant woman looking for her missing husband in Kolkata during the festival of Durga Puja, assisted by Assist Sub-Inspector Satyoki "Rana" Sinha (Parambrata Chatterjee) and Inspector General A. Khan (Nawazuddin Siddiqui).

Plot

A poison-gas attack on a Kolkata Metro Rail compartment kills the passengers on board. Two years later Vidya Bagchi, a pregnant British-Indian software engineer, arrives in Kolkata from London during the Durga Puja festivities in search of her missing husband, Arnab Bagchi. A police officer, Satyaki "Rana" Sinha, offers to help. Although Vidya claims that Arnab went to Kolkata on an assignment for the National Data Center (NDC), initial investigations suggest that no such person was employed by the NDC.