The Lunchbox marketing promises a kind of Indian take on Sleepless in Seattle, where two strangers – through the vagaries of chance and India’s carefully-orchestrated, but not flawless, lunchbox distribution system – begin a correspondence and fall in love before they ever meet. You know, the kind of frothy, featherweight romantic comedy that makes the trip from the subcontinent because it’s going to draw in a wider audience.

For a while, it seems like the film is going to deliver on that promise. Housewife Ila (Nimrat Kaur) exchanges jokey cooking advice with her unseen neighbour, “Auntie” (Bharati Achrekar) upstairs. Gruff accountant Saajan (Irrfan Khan) finds himself saddled with an overly enthusiastic new recruit (Nawazuddin Siddiqui) to train as he prepares for his early retirement – and a lunchbox filled with Ila’s delicious food, besides. We settle in; they’re obviously each straight men (slash women), their respective partners are providing the comic relief, and they’ll fall for each other through the lunchbox notes they exchange.

We learn more about our characters, and we begin to wonder if our initial impressions were incorrect. Ila is trapped in an unhappy marriage, sure, and Khan mourns his dead wife, but this is par for the course if we expect them to end up together. But it turns out Auntie is caring for her comatose husband, who’s been catatonic for over a decade, and Saajan’s assistant, Shaikh, has his own tragic backstory. The pacing is slower than you’d expect for this genre; there are laughs, yes, but a lingering sense of emptiness.

This is because The Lunchbox is less Sleepless in Seattle, more The Apartment; it’s the kind of romantic comedy with as much sadness as sappiness. The emptiness that writer/director Ritesh Batra and editor John F. Lyons convey with their pacing reflects the characters’ aching loneliness, the vacuum at their centre. As the tone of the letters Ila and Saajan exchange become longer and warmer, the tone of the film changes accordingly, with Batra using clever cuts and subtle synchronicity to emphasise the connection between the pair.

But that sense of emptiness never quite dissipates. The Lunchbox is fundamentally a romantic comedy, yes, but it’s not the colourful, heartwarming, predictable film promised by its marketing materials. It exists in the real world, a world of illness and medical bills, regrets and mistakes. This setting means, as the film judders towards its destination, you’re never quite sure what station it’s going to stop at – happily ever after? Maybe not.