Gangavataran is based on the tales of the Puranas, a genre of important Hindu, Jain and Buddhist religious texts. The film used special effects to show mythological miracles and fantasy scenes, credited to Babaraya Phalke, son of Dadasaheb. Gangavataran depicted the Hindu deity Shiva, and the divine sage from the Vaisnava tradition, Narada, played by Chitnis and Suresh Pardesi respectively.
The film tells the Hindu mythical story of river Ganga's descent to Earth. For absolution of his ancestor's sins Bhagiratha vows to bring the heavenly river to the Earth. Pleased with his tapasya, Lord Brahma agrees on sending Ganga. But He asks Bhagiratha to pursue Lord Shiva, as only Shiva could break Ganga's fall. Proud with her heavenly presence Ganga agreed to descend only because of Brahma's orders. Her pride made her believe that her fall would only destroy the Earth. But then Shiva trapped her tight in His hair and only let her go when she asked for forgiveness. Her gentle flow after release then absolved Bhagiratha's ancestors.