Then her longtime bicycle courier, who handles scores of crosstown lunch deliveries each day, makes a rare slip-up. Her husband's delicious meal is accidentally delivered to widowed accountant Saajan (Irrfan Khan), who sends a personal note back with the empty tins, beginning a correspondence with Ila, a platonic connection that feeds their isolated souls.

The actors carry off an immense challenge. They must fall in love at long distance, expressing their emotions through their heartfelt letters. The movie looks wonderful -#8212; deep-focus compositions in bustling, exotic environments -#8212; but the vocal performances are so deft it could work as a radio play.

Khan (the adult Pi Patel in "Life of Pi") draws us in with minimalist underacting. Slowly he peels the layers of his grumpy, glum character like an onion. His notes are at first brusque, then formally polite, then candid, revealing unexpected tenderness and wisdom. Kaur is perfectly cast as the neglected wife gradually realizing she is falling in love with a total stranger.

"The Lunchbox" is a remarkably sensual film. Saajan savors the aromas of Ila's meals. Ila suspects her husband after smelling perfume on his shirt. Saajan recognizes he's an old man because his bathroom smells like his grandfather's. Sound cues are perfectly deployed. The regular thunk of the lunch container on Saajan's office desk is enough to trigger Pavlovian salivation. The clockwork click-clack of his eyeglasses folding and opening signifies the mechanical existence he has settled into.

The setup is reminiscent of "Sleepless in Seattle," and this film works like a sitar riff on Nora Ephron's themes of the vicissitudes of human emotions and love. Shot by Michael Simmons, edited by John F. Lyons and scored by Max Richter, Hollywood talent all, it has the free, fluid feel of a polished Western romantic comedy. Though the film vividly captures the bustle of Mumbai, it has a contemplative pace that allows us to savor the script's wry humor and melancholy irony.

The tone is light-spirited but bittersweet. It allows us to imagine that the characters will live happily ever after but doesn't impose that as the inevitable conclusion. Like the best meals it leaves you elated, satisfied and wanting more.