Cast;
* Ajay Devgan…… Sultan based on Haji Mastan
* Emraan Hashmi…… Shoaib based on Dawood Ibrahim
* Kangna Ranaut…… Rehana
* Prachi Desai…… Mumtaz
* Randeep Hooda…… Agnel Wilson
* Gauhar Khan…… Item number
* Imran Hasnee…… Harish
* Avtar Gill…… Home Minister
* Naved Aslam…… Patrick
* Sanjeev Wilson…… Chandru
* Mehul Bhojak…… Javed
* Arbaaz Ali Khan…… Pathan
* Ravi Khanwilkar…… Vardhan

Plot;
Seen through the eyes of a police officer, Once Upon A Time in Mumbaai traces the changing face of the Mumbai underworld.

The film, set primarily in 1970-Mumbai, follows the rise of Sultan (Ajay Devgan), and his eventual fall, when his protégé Shoaib (Emraan Hashmi), challenges his supremacy, and usurps power to rule the murky underbelly of Mumbai. IMDB describes the film as, “A tale of two gangsters from the eras of past and present, whose lives enter parallel paths as they struggle to survive within Mumbai’s criminal underworld”

Sultan Mirza (Ajay Devgan) is the godfather like figure to the people. He is basically a smuggler. He has his own principles like he never smuggle drugs etc. He does the wrong things in the right way. He is benevolent to the people. His love interest is a film actress, Rehana (Kangana Ranaut).

All lies good for him until he meets Shoaib Khan (Emraan Hashmi). Shoaib is an angry man who is ambitious for power. He wants to be the ‘Don’ ruling Mumbai under his feet. His love interest is his childhood girlfriend, Mumtaz (Prachi Desai). He joins Sultan’s gang and eventually steals the power from Sultan, when he leaves for a personal factor to Delhi.