Very loosely based on Anton Chekhov's The Cherry Orchard, Lester James Peries's MANSION BY THE LAKE follows a family of formerly wealthy, expatriate Sri Lankan landowners, now impoverished, as they return from England to the magnificent country estate they left behind.

Lalith is a chief Clarke of a Government Department. He falls in love with Nilanthi, a newly recruited typist. But Nilanthi is attracted to another handsome young Clarke in the same department named Sagara. Lalith detests this. He starts to suspect each and every act of Sagara and Nilanthi. ‘Dahasak Sithivili’ is based on Lalith’s efforts to prevent himself from getting carried away by these endless suspicions.