Kahaani

Kahaani IPAkani Story is a 2012 Indian Hindi mystery thriller film co written, co produced and directed by Sujoy Ghosh. It stars Vidya Balan as Vidya Bagchi, a pregnant woman searching for her missing husband in Kolkata during the festival of Durga Puja, assisted by Satyoki Rana Sinha Parambrata Chatterjee and Khan Nawazuddin Siddiqui.

A poisongas attack on a Kolkata Metro Rail compartment kills the passengers on board. Two years later Vidya Bagchi Vidya Balan, a pregnant software engineer, arrives in Kolkata from London during the Durga Puja festivities in search of her missing husband, Arnab Bagchi. A police officer, Satyoki Rana Sinha Parambrata Chatterjee, 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.Agnes DMello, the NDCs head of human resources, suggests to Vidya that her husband resembled former employee Milan Damji Indraneil Sengupta, whose file is probably kept in the old NDC office. Before Agnes can provide any further help she is killed by Bob Biswas Saswata Chatterjee, an assassin working undercover as a life insurance agent. Vidya and Rana break into the NDC office and find Damjis file, barely escaping an encounter with Bob, who is searching for the same information. Meanwhile, the attempts to obtain Damjis records have attracted the attention of two Intelligence Bureau IB officials in Delhithe chief Bhaskaran K. Dhritiman Chatterjee and his deputy Khan Nawazuddin Siddiqui. Khan arrives in Kolkata and reveals that Damji was a rogue IB agent responsible for the poisongas attack. In spite of Khans warnings, Vidya continues her search, fearing that Arnabs resemblance to Damji may have led him into trouble. ........

Source: Wikipedia