The dabbawallas of Mumbai are legendary for their near-perfect "tiffin" lunch-delivery service: for every six million lunches sent, only one will fail to reach its intended destination. The Tiffin is about that one time in millions when a box goes astray, changing lives forever.

When a note placed in a tiffin is lost, Kunal is separated from his mother. Years later, the twelve-year-old lives under the thumb of a cruel foster father. Then Kunal meets the tiffin carriers, and a plan is hatched. Along the way, Kunal learns what it means to be part of a family.