The Killer is an action crime drama. The movie revolves around a serial killer and an innocent Dubai-based cab driver, Nikhil Joshi (Emraan Hashmi). One night, a businessman named Vikram (Irrfan Khan) takes Nikhil’s cab. However, Nikhil discovers that this passenger has plans of his own. Vikram plans to use Nikhil to kill all the people who are going to testify against a dreaded gangster. The mere encounter with the serial killer changes the life of an innocent man forever. What happens next, how Nikhil deals with the situation, what happens to Vikram and other people he is planning to kill leads to an interesting climax.