Rani, the daughter of the King of Mangalapuri, is kidnapped during her childhood by Badal, a gypsy from a neighbouring kingdom. He renames her Chamki and rears her to beautiful womanhood and eventually discovers his affection for the child developing into passionate love for the woman.
The King of Mangalapuri, distraught at the loss of his child, consoles himself by making every day a different girl from his kingdom queen for a day and executing her the next morning.
Meanwhile Chamki has met and fallen in love with Vijay, a young soldier in a neighbouring kingdom. By an ironic twist of fate when Chamki is arrested on a theft charge, Vijay is made the escort who takes her to prison. Chamki, however, manages to escape and Vijay, held responsible for Chamki, is punished by his Commander, Karan Singh.
Chamki, in order to secure the release of Vijay, tricks Karan Singh into releasing Vijay from guard duty. When the Commander discovers the ruse, he himself sets out to capture Chamki. Vijay, hiding in Chamki's chamber, tries to save her from arrest and quarrels with Karan Singh who challenges him to a duel. During the duel Badal who is jealous of Vijay tries to stab him in the back but accidentally kills Karan Singh. Vijay is blamed for the Commander's death and he has to flee the country accompanied by Chamki. Badal, however, discovers their hiding place and leads the soldiers to the mountain cave and Vijay is captured. When Chamki discovers that Vijay is under arrest she decides to sacrifice her life in order to save her lover. She offers herself to become "Queen for a Day" in Mangalapuri, and using the law as a tool proves Vijay's innocence and Badal's guilt. The film comes to a suspenseful climax when Chamki is saved from the gallows by Vijay and the joyful reunion of Chamki, now revealed as Rani, and her rightful father, the King of Mangalapuri. The nuptial ceremony of Vijay and Rani brings film to a happy conclusion.
(From the official press booklet)