A wanderer/revolutionary is a dead ringer for a monarch, and takes his place.

Veerangan, a campaigner for democracy, is on the run from monarchists and ends up meeting his lookalike prince Marthandan. The kingdom's Rajaguru (high priest) who wants the throne attempts to poison Marthandan. Marthandan survives but is incapacitated, thus Veerangan has to take his place at the coronation. Veerangan begins a series of 'people oriented' reforms which cause a political upheaval among the elite.—Soumitra