Apur Sansar is the third and final film of the The Apu Trilogy. Apu (Soumitra Chatterjee) is now a graduate and without a job. He lives in a rented room next to a busy railway yard. He finds himself among a large population of the unemployed youth in the city. To pay his rent, he has to sell his books. The job search turns out to be an amusing and a tormenting experience.
Unfazed, He is writing a novel based on his life, which he hopes will make him famous. His life takes a turn, however, when he meets his old friend Pulu. He coerces Apu to travel to his ancestral village to attend the wedding of his cousin, Aparna (Sharmila Tagore). On the boat ride to the village Pulu reads Apu's manuscript and appreciates the work.
On the day of the wedding, the bridegroom turns out to be mentally deranged and the wedding is canceled. The villagers believe if she is not married before the auspicious hour passes, the ill-fated bride can never be married again. Apu primarily of out sympathy for the bride and some convincing by Pulu, agrees to be the substitute groom. He has not even seen her yet.
The marriage takes place and Apu and his young wife return to his Calcutta apartment. Soon, a warm and caring relationship develops. Apu willingly takes up the clerical job that he has so far avoided. The marital bliss, however, is short lived.
Pregnant, she goes to her parents' place and dies during the childbirth. Apu's world shatters as he receives the news of Aparna's death. Sunken in grief, he refuses to even see the child whom he holds responsible for his wife's death. He leaves Calcutta to lead the life of a wanderer.
About five years pass, Apu's friend Pulu, who had been abroad, is shocked to find the child growing wild and not cared for. Pulu goes in search of Apu and requests to take responsibility for his son, Kajal.
Reluctantly, Apu comes back to the village. On seeing Kajal, Apu is overwhelmed by affection. Now it is the child who refuses to accept him as his father. Apu wins over the little boy. The child accepts him as a friend, though not as a father yet. United, they leave for Calcutta to make a new beginning.
· Apu, Apurba Kumar Roy: Soumitra Chatterjee
· Aparna: Sharmila Tagore
· Pulu: Swapan Mukherjee
· Kajal: Alok Chakravarty
· Pulu's wife: Sefalika Devi
· Sasinarayan: Dhiresh Majumdar
· Landlord: Dhiren Ghosh