Miserable at his go-nowhere job, introverted Karthik (Farhan Akhtar) is in love with his colleague Shonali (Deepika Padukone), who doesn't realize he exists. Karthik accepts his loser destiny until one night he receives a mysterious phone call from a man who claims to be himself. Vowing to turn Karthik's life around, the guy on the other end of the line soon becomes his guide and mentor, and Karthik transforms in ways that he hadn't imagined.