Sangram Singh is a blind King. His only daughter, Nalini is very anxious to see that her father's eyesight is regained. The King has issued a proclamation that whoever brings Nagjyothi from Naglok and restores his eyesight, will be given whatever reward he demands.
Vijay, a commoner, secures a job in the King's service as a soldier. Nalini and Vijay accidentally meet and fall in love with each other. Commander-in-Chief Veersen becomes jealous of Vijay and imprisons him on a charge of treason.
Vijay escapes with the help of Bahadur, his jailmate. He then meets Nalini and assures her that he will bring Nagjyothi and, as a reward, claim her hand in marriage.
Both Vijay and Bahadur start in search of Nagjyothi and come to dilapidated temple, where Vijay rescues a Nagkanya from a fierce Rakshas. The grateful Nagkanya gives them two rings to guide them to Naglok. They wear the rings and get down the steps of the tank, when the water recedes, and they reach Naglok.
Nagrani sees in the magic crystal the two strangers coming down the steps of the subterranean passage and is entranced by Vijay's charms. She hypnotizes him and takes him to her chamber. Vijay manages to see in the crystal the place where Nagjyothis are kept and also learns that the key to that place is in a chain worn by the Nagrani. He pretends love to her and at an opportune moment, steals the key from her neck. Followed by Bahadur, he rushes to the Nagjyothi chamber and they take one Nagjyothi each. Just when they come out Bahadur is accidentally caught in a cell.
Meantime, Nagrani finding the key missing, arrives on the spot and catches Vijay red-handed. Enraged at his deceitful conduct, she curses him to become ugly and Vijay is immediately transformed into a detestable creature. Nagrani encloses all his beauty in a jewel and places it on the Linga in the Pathala cave. Vijay begs her for redemption of the curse and she says that if he should marry a noble girl and beget a boy and if that boy should bring the jewel from the Pathala Linga and break it before him, then he will get back all his lost beauty, and if he fails to do this within five years, a serpent will bite him to death. Vijay says that he will do it easily and that Nalini will never let him down when Nagrani further enjoins that if he should disclose his identity to anybody, his head will break into pieces.
Bahadur, who is caught in the cell, throws away the Nagjyothi in utter dejection and cries for help. He is rescued by Nagi, the maid of Nagrani, and lives with her.
Vijay goes to the Palace and restores Sangram Singh's eyes. As a reward he asks for the hand of Nalini and much against the King's will, the marriage takes place. In a fit of anger, Sangram Singh insults Vijay and kicks him off. Vijay leaves the Palace and Nalini too, as a devoted wife, follows her husband's footsteps. They start living in a lonely place near the Pathala cave and, in due course, Nalini begets a boy. At the end of the fifth year, a serpent appears before Vijay and Nalini is shocked. Vijay gives her the Nagjyothi and sends her with the boy to the Pathala cave to bring the jewel. The boy gets into the Pathala cave, but before he comes out with the jewel, Nagjyothi gets extinguished and the boy trapped inside.
Nalini rushes to Vijay broken-hearted and relates what has happened. As directed by him, she rushes to Naglok and appeals to Nagrani to give her another Nagjyothi which alone can save her husband and boy. But Nagrani stubbornly refuses and Nalini, in her frustration, curses her. Nagrani becomes furious and claps Nalini into a cell.
Luckily for her, Nalini finds in that cell the Nagjyothi thrown previously by Bahadur. But how can she escape from the cell? At that psychological moment, Bahadur comes there and opens the door of the cell quite accidentally. Nalini rushes out and reaches the Pathala cave. She rescues her son who comes out with the jewel and breaks if before Vijay. Vijay immediately regains his lost beauty. At the very same moment, Nagrani loses her charms and becomes ugly. She rushes to Nalini, and falling at her feet asks for mercy, and at Nalini's touch Nagrani gets back her beauty.
Nalini and Vijay return to the Palace and live happily ever after.