Jewel Thief opens with a young dancer, Shalini, being felicitated for her talents by the Queen of Sheyat. She is the daughter of a loyal servant to the court who recently passed away. The Queen subsequently promises to arrange for her to dance in court as well. Her young brother, Shishu, is overjoyed. The next day, Shishu is abducted by mysterious gangsters.
In Delhi, the Police Commissioner promises his superiors that he will nab the notorious Jewel Thief by 26 January. A young man, Vinay, attempts to sell a jewel to a jeweller, Seth Vishambar Nath. He sees the commissioner with the Seth and hastily hides. Later, he asks the Seth for a job, but is dismissed summarily by him. He runs into the Seth’s daughter, Anjali on his way out. He meets Anjali once more when she is out with her friends. In their conversation, he points out the true value of her earrings, endearing himself to her father as a true assayer of jewels. He soon starts working for the Seth, driving a hard bargain and raking in the profits.
On two occasions, Vinay is accosted by men calling him Amar. Meanwhile, Anjali comes home to find guests at her house: Shalini and her brother Arjun, the Seth’s childhood friend. At Anjali’s birthday party, Shalini recognizes Vinay as Amar. She claims that he is her long-lost fiancée, and her brother corroborates this. To prove that he is not Amar, Vinay shows them his right foot, on which Arjun says Amar had six toes. After the party, Vinay goes to meet his mother and gifts her an ornate necklace he brought with his first salary. His father, the Police Commissioner, is immediately suspicious, and takes the necklace to the Seth. The Seth dismisses his fears, telling him that Vinay was indeed telling the truth.
Meanwhile, haunted by memories of Amar, Shalu is distressed, and Vinay consoles her. The same night, the spirited Anjali makes advances towards Vinay but he tells her to go back to her room. Shalu and Vinay spend more time together and grow affectionate towards each other as she shares with him the tragic story of her parents’ death. The Police Commissioner, in the interim, has received news that Shalu’s engagement ring, a gift from Amar, was stolen from Pune a year ago. The Commissioner begins to suspect that the absconding Amar is the sought after Jewel Thief.
The Seth entrusts Vinay with appraising his diamonds late in the night. On the night he is to start, he is with Shalu when she receives a letter from Amar and goes out. A group of ruffians attack her and take the ring from her. Caught up in these events, Vinay is late to work. He rushes to the store and finds the doors locked. Disappointed, he returns to the Seth’s house to speak to him. While he is with Anjali, the Seth arrives. He is shocked to see Vinay, under the impression that he left Vinay in the shop. They quickly realize that his place must have been taken by his doppelganger, Amar, and they hasten to the store, only to find it robbed of the Seth’s priceless diamonds.
Vinay decides to investigate the robbery. Following ‘Prince’ Amar’s trail, he reaches the Roman night club when he is informed that the club’s dancer, Helen, is Amar’s paramour. Dressed in Amar’s clothes, he infiltrates her bedroom, which sports a large portrait of him on the wall. When she falls asleep, he hears another man come in. He follows him, but to no avail. The mysterious Amar calls Helen the next morning, and hot on his trail, Vinay boards a train to Pune. Though he cannot find Amar in the train, he runs into Arjun, who is also searching for Amar. When he alights, he is greeted by a woman named Julie who mistakes him for Amar. She takes him with her to a plane, and on the flight Vinay meets Amar’s gang of criminals. It is revealed that Julie is pregnant with Amar’s child, and Vinay in Amar’s guise promises to marry her soon. The gang moves to a Rana’s manor, and they steal his jewels. Still with them, Vinay is implicated and his photograph is printed in the newspaper. Yet again, he meets Arjun, who tells him that he mistook Amar for Vinay and spent two days with him. They reach Arjun’s hotel only to see that he has escaped yet again.
Vinay and Arjun go to Gangtok in search of Amar. The Police Commissioner arrives there as well to apprehend Amar. Shadowing Amar’s footsteps, Vinay meets a woman named Neena, also one of Amar’s dalliances. He speaks to her to extract information. A few hours later, he sees Shalu in Gangtok. She tells him that she has come there without her brother’s knowledge, and they renew their promises to each other. With her brother Arjun’s blessings, they decide to marry each other.
Soon after, Vinay spots Neena in danger and he follows her when she is abducted. He is lured into Amar’s den, and further entangled in the criminals’ dastardly plots. Will Vinay ever meet his double? Who is the real Jewel Thief? Will he be brought to justice? All of these questions are unravelled in the thrilling climax of the film, shot in a resplendent set to replicate a palace in Sikkim.
Taking elements from Hitchcock’s classics To Catch a Thief (1955), Vertigo (1958) and North by Northwest (1959), Jewel Thief was a resounding hit when it was released. It was screened in a number of film festivals, and a sequel for the film was released in 1996 under the title Return of Jewel Thief, with Dev Anand and Ashok Kumar reprising their roles from the original. The film still remains among the iconic movies made in the 1960s, marking a move to colour, new urban locales in shooting, and a new kind of heroine with Tanuja’s Anjali.