Hero Vinay (Dev Anand), son of the police commissioner (Hussain), finds himself repeatedly mistaken for notorious jewel thief Amar. He is accused by Shalini (Vyjayanthimala) of being the man who promised to marry her. The accusation is substantiated by her brother (Ashok Kumar). Vinay masquerades as Amar to try to crack the gang, even as it appears that Amar too masquerades as Vinay, leaving the audience guessing for most of the film on the identity of the hero. Eventually, Amar turns out not to be her brother at all. This cult movie, using concealed bars, moving walls and hidden safes, snow lifts and aeroplanes, determined the look and fashion of many of the late 60's Hindi cinema.