The story begins with Venkat Subramaniam, an Indian professor of mathematics, software engineering, and a genius, teaching mathematics in his village to kids when a postman comes with a letter. The letter is from British mathematician Perci Trachtenberg, widely regarded as the world's greatest living mathematician, who invites Venkat to a high rolling casino in London. Venkat tells Perci about an equation that could not only change the dialogue on mathematics forever, but one that has already left an indelible impression of guilt — for many painful reasons — on Venkat's life. It is shown in the past that the reclusive genius Venkat has cracked a theory that could redefine the principles of probability and randomness. Venkat tries to use this experiment in a game called Teen Patti, which he plays on the Internet. According to this experiment if a person playing Teen Patti knows the three cards with one of the players he/she can guess the other cards with the rest of the players and therefore can guess who is going to win with the theory of probability. Venkat succeeds on his theory and submits his report to the institute where he teaches, but they reject his report. Venkat is sure about his theory and wants to try out in reality with live players. So he talks with younger professor Shantanu Biswas about his theory and tells him to get three students to try out this experiment. Shantanu arranges three students — Sid, the college rockstar; Aparna or Apu, the studious geek, who has a crush on Sid' and Vikram or Vikku, the boy next door. They come together and start playing the game. Venkat's theory, like the last time, proves to be successful. Venkat says that after a few more games he'll be sure to crack his equation and even be able to study it better. Shantanu tells him that he should try using his theory in the real world, where there are people who actually gamble and play Teen Patti, i.e. in underground dens or 'addas'. Although Venkat has no interest in the money that could come from practicing his equation to crack Teen Patti, he eventually succumbs to Shantanu's charismatic persuasion. Soon, with the help of his new students, they explore the addas of wild Bombay. Later another student from the institute, Abbas, the richspoiled brat joins the gang and arranges for them parties in casinos, private clubs, etc. But what starts out as an experiment between a charismatic young professor and an eccentric older one soon descends into a game neither of them can control. The money they earn gets stolen; someone is blackmailing them; they get greedy about money and, in the course of time, they change into different people and even start betraying each other.
Music of the film is composed by Salim-Sulaiman and the lyrics are penned by Ajinkya Iyer and Irfan Siddiqui. Most of the tracks have a western feel associated to them. The songs are remixed by Abhijit Vaghani. Sunidhi Chauhan's rendition of the song Neeyat Kharab Hai was widely acclaimed.
Production
The film was shot in India and England. Production designer Ayesha Punvani created gambling dens in places like abandoned train yards, dockyards, abandoned factories, mills that have been shut down and an ice factory.
Teen Patti is inspired by the English film 21. The end of the film when Amitabh Bachchan refuses to accept Isaac Newton Award for Applied Mathematics is inspired by the refusal of the Fields Medal by the Russian mathematician Grigori Perelman.
