The film commences in the UK, where Colonel Viren Nanda (Jimmy Shergill) visits the captured terrorist, Omar Zafar (Danny Denzongpa), in his holding cell. During the meeting, Viren informs Zafar that he will soon be extradited back to India under a newly established extradition treaty. However, Zafar’s men, led by Hamid Gul (Jaaved Jaffrey), launch a shocking attack, murdering the guards and killing Viren before Zafar dramatically escapes via helicopter. Before his escape, Zafar offers a $5 million reward for anyone who can steal the famous Koh-i-Noor diamond from the Tower of London, under one condition: the thief must be Indian, a ploy to obstruct the imminent extradition treaty.
Not long after, Rajveer Nanda (Hrithik Roshan), seizing the opportunity, executes the theft. When Zafar's men discover the theft, they head to Shimla to confront Rajveer, only for him to demand a staggering $20 million instead of the previously promised amount. Tensions flare, leading to a skirmish where Rajveer narrowly escapes, prompting the Indian government to mobilize its ISS forces to recover the Koh-i-Noor and protect the treaty.
In a twist of fate, Rajveer encounters Harleen (Katrina Kaif) in a restaurant. She is waiting for her internet date, “Vickie.” Rajveer, adopting the alias "Vickie," charms her while secretly dealing with Zafar’s men. A sequence of chaotic events unfolds when Harleen accidentally runs over Rajveer; he forces her to treat his gunshot wound and inadvertently manipulates her into compliance.
The following day, government officials, including Zorawar (Pawan Malhotra), confront Harleen at her workplace, threatening to reveal her involvement unless she cooperates. In a daring move, she seizes a gun to escape alongside Rajveer, but the journey ahead is fraught with danger and miscommunication leading to car chases and misunderstandings. Their relationship evolves amidst the chaos, as Harleen initially distrusts Rajveer but gradually realizes their connection.
Their dynamic shifts dramatically when, during a pizza outing, Rajveer reveals the Koh-i-Noor to her, deepening her disbelief. As Zorawar’s men close in, Rajveer resorts to a tranquilizer dart, ensnaring Harleen in yet another narrow escape. The two find refuge on a beach, but when they wake up in Prague, Rajveer's past catches up. With INTERPOL hot on their trail, they must navigate through deception, broken trust, and betrayal.
An intense sequence ensues when Rajveer confronts Hamid Gul at a casino, leading to a tense showdown about Zafar’s whereabouts. Meanwhile, Harleen is captured but later reunites with Rajveer when he sacrifices himself, diving off a bridge to protect her. As Harleen seeks solace after witnessing Rajveer’s supposed demise, she learns of his past and encounters his family.
The plot thickens when Zafar abducts Harleen, aware that she possesses crucial information about the Koh-i-Noor. Rajveer, on a vengeful quest, infiltrates Zafar’s domain, strategically planting explosives to trap them. A thrilling climax arises within the aircraft when Rajveer faces off against Zafar, ultimately vanquishing him but not without peril.
In the aftermath, Rajveer finds himself in a hospital, dealing with the ramifications of his escapades. He learns from his superior about the need to sever ties with Harleen for her safety. But fate takes an unexpected turn when Harleen disguises herself as a nurse, administering a sedative to aid in their escape. As Rajveer regains consciousness, revealed to be home at last, they joyfully reunite with his family, thereby evoking hope and love amid the tumultuous journey they have weathered together.
Thus, the story concludes with Rajveer and Harleen standing resiliently by each other's side, embodying a bond forged through both adversity and thrilling encounters.
