A police officer named Harishankar, who got demoted recently for physically assaulting his senior, is our central character. The short-tempered guy gets a fake gold chain case on the day he rejoined the force, and the investigation leads him to the possibility of this case having a pattern. Certain unprecedented events happen around this case, and Harishankar gets accused of things he has no involvement in. We see how he solves the mystery around this case in Officer on Duty.