Inji Iduppazhagi story is about Sweety (Anushka) an obese and happy girl who doesn’t care about her personality. Her mother (Urvashi) tries hard to hook up matches with NRI brides. Abhi is an NRI who comes to India to make documentary on Swatcch Bharat. Abhi and Sweety become good friends. Simran (Sonal Chauhan) works for an NGO and she joins Abhi. Satyanand (Prakash Raj) has a slimming center called Size Zero where he guarantees enormous loss of weight in short time. On the insistence of her mother, Sweety joins that slimming center. Rest of the story is all about what happens next.