Events in India's history — from the Emergency and the famous Cricket World Cup win to the Punjab riots , unfold from the perspective of an innocent Sikh man Laal Singh Chaddha, a person with a low IQ but high optimism. Laal is able to achieve everything under the sun but his childhood love continues to elude him.

An ex-army officer, Kabir, becomes a teacher in Kashmir in a school that is in a miserable condition. Things take a turn when Kabir finds a notebook, left behind by the previous year's teacher Firdaus.