Balaji and Milan Luthria's Once Upon A Time In Mumbai traces the changing face of the Mumbai underworld and how it all started.

The film is set primarily in 1970s Mumbai. It follows the rise of Sultan (Ajay Devgn) and his differences with protégé Shoaib (Emraan Hashmi), who challenges his supremacy and usurps power to rule the murky underbelly of Mumbai.

The movie is presented in a retro chic style and is a glamorous and powerful rewind to the golden era.