MARDAANI 2 is the story of a psychotic rapist trying to challenge the police. Shivani Shivaji Roy (Rani Mukerji) is now the SP of Kota, Rajasthan. In this town, a girl named Latika (Tejaswi Singh Ahlawat) attends a fair where she fights with her boyfriend Monty (Pratyaksh Rajbhatt). A mysterious person, Sunny (Vishal Jethwa), witnesses the way Latika blasts Monty. He has an issue with such outspoken women and on an empty stretch, he abducts her. He takes her to an abandoned place where he brutally tortures Latika, rapes and then kills her. Shivani is shocked with the violence but carries out the investigation immediately.
At the press conference, she calls the murderer 'dedh shaana'. This hurts Sunny and he decides to teach Shivani a lesson. He sends her flowers with a taunting note. He sneaks into her house and steals her clothes and accessories. He wears her saree to trap a journalist Kamal Parihar (Anurag Sharma) and eliminates him, as part of the contract given to him by a local politician Panditji (Prasanna Ketkar). Sunny then smartly gets employed in the tea stall outside Shivaji’s police station. Hence he gets access to visiting the police station and even eavesdropping what the cops are talking about the case.
When a kid, who had seen Sunny, comes forward to identify him, Sunny kidnaps him from the police station toilet and kills him. Shivani hence faces backlash for what is termed as a lapse on her part. She is transferred. But as everyone is busy with Diwali celebrations, the replacement is expected to take charge only 2 days later. Hence, Shivani has 48 hours to crack the case and nab Sunny. What happens next forms the rest of the film.