Piku (Deepika Padukone) is a working girl in a cosmopolitan city. An architect by profession, she is a simple, Independent and strong girl from Delhi. She is grounded and rooted to what matters most - family... and in this case, her father, who she looks after. Piku is the kind of girl who doesn't shy away from responsibilities. The film takes audiences through the ups and downs and everyday problems she faces with her father.
Baba - Bhaskhor Banerjee (Amitabh Bachchan) is Piku's father. He is retired and spends most of his time obsessing about age-related issues. He is stubborn, dramatic and comes with his own set of problems... he has very specific, but unconventional, likes and dislikes and fixed ideologies. He is not a man who enjoys socialising. Baba is not the hero here, but the film takes a look into his household.
Rana - He (Irrfan Khan) is the outsider who has nothing to do with the Banerjee family but gets entangled with them and all their drama. He is the owner of a taxi service, who comes with his own quota of problems and then happens to get some more, when he finds himself entangled in the Banerjee family. Things take a funny turn once Rana gets involed with the family.