Mili is a survival thriller film based on true events and a remake of the Malayalam hit film Helen released in 2019. The story is set in Dehradun where Mili Naudiyal (Janhvi Kapoor) who lives with her father (Manoj Pahwa) has just graduated and looking to travel to Canada to do her master's. Mili also has a boyfriend named Sameer (Sunny Kaushal) who is in search of a job. Meanwhile, Mili takes up a part-time job at a fast-food joint called Doon's Kitchen inside a plush mall. One day while working at the fast-food joint her manager unknowingly locks her in the freezer room. At -18 °C, Mili has no means to contact or ask for help as tries to survive in the freezing cold by doing everything to keep herself alive. On Mili not reaching home, her father and Sameer report to the police. Will the police succeed in tracing out Mili, will Mili be able to survive?