John Biswas' (Bachchan) life is torn apart when his young granddaughter Angela Roy is kidnapped. Though Martin (Nawazuddin), the police inspector who handled the case has quit; John refuses to do so. Eight years after her disappearance, a similar kidnapping puts the spotlight back on the case. John, Martin and a new Inspector Sarita Sarkar (Vidya Balan) begin their hunt for the criminal. What is intriguing is that the modus operandi seems to be similar to the Angela case.