Piku Banerjee (Deepika Padukone) is a Bengali architect residing in Delhi, with her 70-year-old father, Bhashkor (Amitabh Bachchan). Bhashkor has problems with chronic constipation and traces every problem to his bowel movements. His habits often lead to quarrels with the servants and irritates Chhobi Mashi (Moushumi Chatterjee), who often visits them. Piku loves her father and, as her mother has died, takes good care of him but gets extremely irritated with him at times because of his eccentricities. Her colleague, Syed Afroz (Jisshu Sengupta) is a good friend, and she is a regular client of Syed’s friend, Rana Chaudhary’s (Irrfan Khan) taxi business. Rana has his own family problems with his mother and sister.
Piku wants to sell their ancestral home in Kolkata, Champakunj, but Bhashkor objects vehemently and decides to go to Kolkata. Piku has to accompany him, since she cannot let him travel alone. Bhashkor brings up his constipation problem and decides to travel by road. Due to Piku being very problematic with other drivers of Rana, they back away before Piku’s trip. Piku, disappointed with the agency tries to book a flight, but soon, Rana arrives at their home to take the family to Kolkata himself, without informing his family about the trip.
On the way, the group encounters many incidents, including Rana on the verge of losing patience due to Bhashkor’s fussy behaviour and constipation. They finally reach Kolkata, where Piku’s relatives live in the old house and Bhashkor asks Rana to stay for some time. Piku and Rana go out in the city and gradually grow close. Rana also subtly hints not to sell the house during a discussion.