The film that cinematically narrates the history of Sri Lanka’s leftist politics over a period spanning two generations records the political, sexual and family relations of a series of men and women.

Reginold Wijayawardhana, attorney at low studied in Great Britain. He toiled ceaselessly to win for the poor class the labour rights. A popular leftist politician of the 50’s who won everybody’s heart. His wife Helan descendent of a Sri Lankan family resided in Britain is a house wife having radical views. The two children in the Wijewadhana family, Sarath the eldest is a lawyer by profession. Wasantha the youngest is still a student. He plays cricket for his school team. After the death of Wijewardhana, Sarath follows his father’s political lineage.

Wasantha falls in love with a school girl Nirmala who lives with her mother Seetha. Looking after the property inherited from her dead husband Seetha was widowed in her youth has a good taste for arts and quality music.

Hearing of her daughter’s affair Seetha one day invites Wasantha to her home. Wasantha takes his brother too for the journey and Seetha satisfied with the two brothers approves of the affair. But Sarath who has similar taste as that of Seetha develops an affair with Seetha despite strong objection from his brother. Conflict between two brothers prompts Wasantha to leave his brother. Meanwhile Seetha who had approved of the affair between Wasantha and her daughter now comes to oppose it.

But the youngsters wed in secret and Sarath who desired to follow in his father’s footsteps begins to dabble in politics but does not achieve much success due to lack of experience in working with the people. Despite many upsets Sarath is finally pitted against Punchibanda Dissanayake a right wing politician and brother of Seetha’s late husband who is also an influential businessman in the area.

At the election fever rises Punchibanda uses Sarath’s illicit affair with Seetha in the campaign to attack the left leaning candidate. Sarath loses the election and Punchibanda is elected to parliament.

Disheartened Nirmala who failed in her attempts to stop the affair between her mother and Sarath, commited suicide. Wasantha following the death of his fiancée too committed suicide.

Though losing everything Seetha and Sarath continue with the affair which was disapproved from everyone.

Cross section of the actions to Sri Lankan Politics from the 50’s to the 90’s that had remained unexplored now, finds a place in “Thahanam Gaha”