"The story is about a mysterious phone call which changes the life of an introvert Karthik Narayan (Farhan Akhtar) from being a 'nobody', to a famous successful man having the most beautiful girl, Shonali Mukherjee (Deepika Padukone) as his girlfriend, but with a price. But when he reveals the truth to Shonali, he loses everything he gained. Which leads one to wonder... who was the caller?
