Sulochana a.k.a. Sulu (Vidya Balan) leads a middle-class lady from Bombay, living with her husband, Ashok (Manav Kaul), and school-going son, Pranav (Abhishek Sharma). A school dropout, she is happy winning prizes in contests held on radio or in-game competitions in her housing society and the like but yearns to do something to supplement the income of her husband who works in a garment factory. Her father, two elder twin sisters and brothers-in-law keep asking her to take up a permanent job.

One day, she finds out that Wow FM radio station is on the lookout for a new radio jockey. Although she has no experience, she offers herself for the job. At first Wow radio head, Maria (Neha Dhupia) sees a spark in her due to her simplicity and honesty, and hires her on a handsome salary, much to the discomfort of the show’s producer, writer and RJ Pankaj (Vijay Maurya). The only hitch is that it’s a late-night show for which Sulu has to be at the radio station every night. She is trained to talk sexy and naughty to the callers on the live show.

Sulu nails it in her first show, and her popularity keeps growing.Soon, Ashok and Sulu’s other family members start voicing their reservations about Sulu talking to autorickshaw drivers and the like, that too, on topics which could be considered taboo. But Sulu is adamant to continue with the radio show as she experiences a new-found confidence.

Ashok loses his job and his frustration grows further. Things take a turn for worse when her son pulls a huge one at school, and Sulu has to contemplate between the life she has mad for herself, and the one she had been living before.