Officer on Duty is a crime drama centring around Hari Sankar, a Circle Inspector in Kerala Police, who is investigating a petty crime in his local station. What starts off as a fake-gold-jewellery pawning case spirals out into an investigation of organized crime and series of murder. The unfolding of events assumes added significance as they are linked to the personal and family life of Hari Sankar, as well as new crime trends in contemporary Indian society.