Anyone unaware of the Mumbai dabbawalas soon becomes enlightened in this film of India, where much is made of the dabbawalas picking up lunches from restaurants and homes to be delivered to (usually husbands) at work. This is how widower Saajan (Irrfan Khan), who's shortly due for retirement, comes into epistolary contact with the much younger Ila (Nimrat Kaur). Ila is trying to spice up her married life by cooking wonderful meals for her husband, although the (apparently virtually impossible) happens and Saajan receives (with huge pleasure) the lunch prepared by Ila. Soon Ila and Saajan are sending notes to each other via the lunchbox, and the notes become increasingly friendly.
Ila's husband is having an affair and she tells Saajan that she's thinking of moving to Bhutan where the cost living is about 80% less than Mumbai, and Saajan bravely suggests that he move there too. In her reply, Ila suggests that they meet in a local restaurant. Unfortunately Saajan goes there but only looks at her from a distance, finding her beautiful but considering that he is far too old for her. In the end, there is no definite end.