Pratignya' is the story of Sudha's vow made to Rajababu. Sudha and Rajababu's son Kumar fall in love and get married. Rajababu can't accept a farmer's daughter as his daughter-in-law and asks her to keep the relation a secret. Kumar goes abroad for business. Sudha gets pregnant but she doesn't reveal the name of her child's father. She leaves the village and gives birth to a son who is abandoned at the orphanage by her father. Circumstances bring Sudha to the orphanage and she develops a bond with her son Shyam. Kumar in the mean while has become an alcoholic. Kumar starts believing that Sudha is a characterless woman. Kumar adopts Shyam. Kumar's wedding is fixed. But circumstances makes Rajababu realize his mistake and he reveals the truth and accepts Sudha as his daughter-in-law.