The land of Nags was a prosperous and peaceful country. Nag was their State Deity. The deity had blessed the State with two pieces of Mains (crest jewels) which, if joined together, could have made the State invincible.
In Shigali, the State had a blood thirsty tyrant as a neighbour who had an eye on these pieces of Manis. Like a wounded leopard, greedy and furious, he attacks the State spreading death and destruction in his wake. He somehow succeeds in getting possession of one piece of Mani from the Nag Temple. The State Deity prophesies the death of Shigali at the hands of Nagrani. Shigali orders he arrest but the Dewan of Nag State persuades her to flee to wage the freedom fight from outside and asks his own daughter to impersonate as Nagrani. Unaware of this Shigali imprisons Dewan's daughter and other Rajkumaris in a huge cage.
Nagrani enters Shigali's Kingdom in disguise and by sheer coincidence meets Sagar, the hero, and Damroo, his comedian friend. Sagar is the son of the imprisoned Senapati and is living in disguise in Shigali's state with his sister and mother. Both Sagar and Nagrani join hands to seek entry into the palace of Shigali. The Nagrani is presented to Shigali as an Arabian beauty by Sagar, who poses as an Arabian merchant. The Nagrani dances her way to Shigali's heart. She remains in the palace and Shigali begins to trust her. Meanwhile Shigali makes futile efforts to get the secret about the second piece of the Mani from the imprisoned Senapati. By a strange coincidence Shigali comes to know that Sagar is the son of Senapati. He gets Sagar's sister killed when the girl was getting married. Sagar infuriated takes a pledge to avenge his sister's death and kills Shigali's henchman, Vilas, who had murdered her. How the Nagrani succeeds in meeting her sisters and the Senapati? How she and Sagar succeed in getting possession of both the pieces of the Mani and then, later, how they lose them to Shigali? What happens to them and how they are saved is anybody's guess.
Cobra Girl is the story of a brave girl who staked her life to win back independence for her country, who fought not only with wicked and cruel men but also with wild animals let loose on her. It is the saga of intrepid and unrelenting courage, a spectacular panorama of the fight between virtue and vice-all presented in the glorious Eastmancolor.
(From the official press booklet)