Siddharth and Trisha are a happily married couple until Trisha gets pregnant and things start getting complicated. Sid is not ready for a baby as he is just a struggling music composer, yet lies to Trisha. On his friends' advice, Sid starts reading pregnancy books and following Trisha's daily routine by putting a balloon in his shirt. Finally, Trisha gives birth to a baby girl and starts devoting all her time to the baby. Trisha's mother feels that Sid is a careless person and can not take this responsibility, at which Sid makes a desperate attempt to behave like a family man but fails, as on one occasion he takes his baby for a walk but forgets her in the market. Frustrated, Sid ask for help from Trisha's brother-in-law Ranveer, who is a typical family man. Ranveer reveals to him that when he gets frustrated, he makes a business trip excuse and stays in a hotel room to enjoy his life as a bachelor. Sid takes on his idea and starts staying in a hotel, with the excuse of working overnight in studio. But soon he has to cut down his idea, due to an added expense at home as Trisha decides to hire an expensive governess. Sid, then, without telling Trisha, goes for a cheaper solution by shifting to a shared PG along with Manav, a dope-head bachelor. Sid takes Manav's advice and starts living a carefree life.

Then enters Shekhar, a young neighbour, who saves the baby when she gets locked in and thus frequently comes to meet Trisha, which makes Sid jealous. Sid realises the value of his family when Manav is hospitalised and none of his family or friends are around to take care of him. Filled with guilt, Sid confesses the PG secret to Trisha, who in anger throws him out. Sid seeks Ranveer for advice, only to discover that Ranveer is having an affair. Ranveer confronts Sid by telling him that he has also cheated Trisha by devoting time apart from his family. Sid realises his mistake & after repeated apologies by Sid, Trisha reveals that she also got involved with Shekhar and is now pregnant. Sid rushes out of the house along with the baby and later he realises that he should forgive Trisha for their child and also because all these happened because of him and thus forgives Trisha. To which Trisha surprises him by telling that she is not pregnant with Shekhar's child but with their child. Sid and Trisha reunite and start living a happy family life along with their baby.

Towards the end Sid is in the park playing with their two children and giving "Fatherhood Notes" to other fathers in the park. He calls Trisha to give her the good news that a music company has finally asked him to compose a song for their album. Trisha is now a working woman and tells Sid that she will be late because of a deal which needs to be completed. Sid says that he is fine to look after the kids till she returns. As the camera pans out, it shows Trisha relaxing in a hotel room with a glass of wine.