The film narrates the story of a spy who is on an undercover mission codenamed 'Asambhav' to Ticino, Switzerland. The high action drama and danger of an undercover mission, the twists and turns, the underlying tension, the escapades and the chases, accompanying the glamour and oomph, all form a part of the story providing edge of the seat entertainment to the viewer.
The action unfolds in Ticino Switzerland where a high-ranking diplomat of India (Mohan Agashe) is on a private holiday along with his daughter Kinjal (Dipanita Sharma) in Lucerne, Switzerland.
A conspiracy of international dimension is hatched by the mastermind criminal Ansari (Milind Gunaji). The high ranking diplomat and his daughter are kidnapped on his insistence by the Mabros Mercenaries (Shahwar Ali and Gang) and held under siege at the Brissago Islands. The plan is to exchange the diplomat with the international terrorist group Al-Hamas led by Yuzan (Mukesh Rishi) for a price of $50 million.
Unknown to Mabros, by sheer chance the situation is conveyed to the Army Headquarters. It is here that a decision is taken by the senior staff to send a Captian, Aadit Arya to Ticino, Switzerland to evaluate the situation and to bring the diplomat back safely. Thus starts the journey of Capt. Aadit Arya, which leads the viewers into a web of deceit and high action drama.
To generate the $50 million for Yuzan to pay the Mabros mercenaries, Ansari enlists the help of Sam Hans (Naseeruddin Shah) and Brian (Tom Alter) who in turn asks Dabral (Arif Zakaria) and his brother to con Alisha (Priyanka Chopra), a struggling pop singer, into the conspiracy.
On their arrival to Ticino, Alisha's friend and companion, Shilpa is killed by Ansari and his men. Caught on unknown ground and in the midst of confusion, Alisha runs for help to the Indian Embassy where Capt. Arya notices her predicament and offers his help. Accompanying Capt. Arya is his official escort, Atul Bhatnagar (Jameel Khan), an intelligence officer who is completely oblivious to the true identity of Arya and the mission. Arya along with Alisha and Bhatnagar penetrates the under siege Brissago Island as a journalist and find out that there is a Mole in the Indian Embassy at Locarno. The security incharge, Parmar (Yashpal Sharma), friend of Sam Hans, stumbles on the conspiracy. Sam Hans realizes why he was used in the plot and is now determined to get the money for himself.
The battle for the $50 million between Sam Hans, Ansari, Mabros and Yuzan complicates Arya's mission more. He now not only has to rescue the diplomat but also wipe out the international web of criminals. How he manages to uncover the hidden truth behind the conspiracy is the mission Asambhav.