Irrfan Khan as Saajan
Nimrat Kaur as Ila
Nawazuddin Siddiqui as Shaikh (Saajan's Colleague)
Denzil Smith as Mr. Shroff
Bharati Achrekar as Mrs. Krishnan
Nakul Vaid as Ila's Husband
Yashvi Puneet Nagar as Yashvi
Lillete Dubey as Ila's Mother
Middle class housewife Ila is trying once again to add some spice to her marriage, this time through her cooking. She desperately hopes that this new recipe will finally arouse some kind of reaction from her neglectful husband. Unknowing to her is that the special lunchbox she prepared has been mistakenly delivered to an office worker Saajan, a lonely man on the verge of retirement. Curious about the lack of reaction from her husband, Ila puts a little note in the following day's lunchbox, in the hopes of getting to the bottom of the mystery.
This begins a series of lunchbox notes between Saajan and Ila, and the mere comfort of communicating with a stranger anonymously soon evolves into an unexpected friendship. Gradually, their notes become little confessions about their loneliness, memories, regrets, fears, and even small joys. They each discover a new sense of self and find an anchor to hold on to in the big city of Mumbai that so often crushes hopes and dreams. But since they've never met, Ila and Saajan become lost in a virtual relationship that could jeopardize both their realities.