Plot

India's top spy Tiger and his love Zoya battle the dark world of intelligence and espionage that forbids its soldiers from loving the enemy.

In the dark world of intelligence and espionage, all information is guarded in the name of national security. But some stories escape the fiercely-guarded classified files, stories that become legends. This is one such story, a story that shook the very foundation of this dark world. In a government employees' neighbourhood in New Delhi, lived a rugged, handsome and mysterious bachelor about whom his neighbours knew nothing. That was because he was India's top spy, an officer with the Research and Analysis Wing (RAW), India's external intelligence agency. This man was known even in official corridors as TIGER. Tiger is sent on a relatively easy and safe mission to Dublin, Ireland to observe a scientist of Indian origin who is suspected of sharing his research findings with the Pakistan defence establishment. Tiger attempts to meet the scientist but is not successful. He tries to befriend the scientist's part-time home caretaker Zoya. As Tiger gets closer to Zoya, he begins to discover his human side. For the first time in his life, Tiger falls in love. What follows is a tumultuous journey that Tiger and Zoya embark upon, battling the dark world of intelligence and espionage that forbids its soldiers to fall in love.—Official source

India and Pakistan have fought 4 wars in the last 60 years. ISI and RAW continue this war, out of public eye, on a daily basis. Their stories are never made public under the garb of National security. Still, some stories come out.

An agent code-named "Tiger" (Salman Khan) - India's top spy and an officer of the Research and Analysis Wing (RAW) - is conducting a mission in northern Iraq. Tiger is forced to kill one of his own men Rabinder (Samar Jai Singh) who has defected to Pakistan's spy agency Inter-Services Intelligence (ISI). Rabinder calls the ISI for extraction as soon as he is found by Tiger and they both end up in Rabinder's hideout after a chase.

Rabinder admits that he betrayed his nation for money. Tiger is livid that Rabinder's betrayal cost the lives of several RAW agents. Rabinder tried to recruit Tiger for the ISI, but Tiger shoots Rabinder when he raises his gun at Tiger. Tiger subsequently kills many ISI agents in his escape.

Tiger returns to India and reports to his boss, Shenoy (Girish Karnad), in New Delhi. Shenoy advises Tiger to take some leave, but Tiger insists to be deployed on the next assignment, like he has been for the last 12 years. Shenoy notes that Tiger's salary is lying untouched in his salary account for the duration of his service. Tiger has a decade old furniture in his government apartment and has no books or even pictures in his house.

Tiger admits to Shenoy that he is a bit of a loner & has never had feelings for anyone in his life. He has no girlfriends as he is never in town for long. And plus, he can never reveal his true profession to any potential girlfriend. Shenoy tells Tiger that he was also young once & had feelings for a girl. But he gave up the girl for his duty & regretted it ever since.

Tiger is immediately sent on a mission to Dublin to observe a scientist of Indian origin, Professor Anwar Jamaal Kidwai (Roshan Seth), who teaches at Trinity College and is suspected of sharing his findings with the Pakistan defense establishment. Fellow RAW agent Gopi (Ranvir Shorey) accompanies Tiger on this mission. Kidwai has the knowledge of India's anti-missile technology which is able to neutralize any missile that Pakistan has in its arsenal. Kidwai left his government job and started teaching in Dublin. Shenoy says that India only suspects Kidwai and hence asks Tiger to gather proper proof of his wrongdoing.

Tiger poses as Manish Chandra, a non-fiction author writing a book on finest Indian minds, involving Kidwai and other Indian academics. Tiger meets the scientist but fails to spend enough time for his observance, and instead begins to spend time with scientist's caretaker Zoya (Katrina Kaif), who is studying at a local dance academy. He tries to befriend Zoya to extract information, and he begins to discover his human side as he grows closer to her.

Zoya introduces Tiger to Kidwai, and he agrees to his proposal to be Kidwai's "constant companion" for a few days. Zoya comments that Tiger does not look like a writer as he has very coarse hands, like that of a wrestler. Over time, Tiger and Zoya fall in love, and she invites him to "My Son, Pinocchio", a college play sponsored by Kidwai which she choreographed. Tiger is attacked and robbed at his residence by a person suspected to be an ISI agent.

Gopi repeatedly warns Tiger not to fall in love with Zoya, but he does. Tiger gifts Zoya a book on stars, as he had seen a star themed decoration in Zoya's hostel room. Zoya is touched by this gesture and tears up. Zoya says that her father used to take her out on a jeep to watch the stars outside of the city. Here father eventually passed away and she believes he became a star and is blessing her from the skies.

After seeing the assailant on the day of the play, Tiger chases him through Dublin, which leads to Tiger publicly preventing a Luas train crash. During the play, Gopi calls Tiger to inform him of activity at Kidwai's house, which is strange since Kidwai is at the play in college. Tiger heads back to Kidwai's home and there Tiger discovers Zoya is an ISI agent tasked to steal Kidwai's research. Zoya refuses to hand over the research to Tiger and return to India with him. Tiger cannot believe that Zoya does not love him. He lets her go after combating an attack by Feroz (Troi Ge Borde), an ISI agent, who is revealed to be Tiger's mystery assailant.

For a while Tiger takes a desk job in India & remembers his precious time with Zoya. Back in India, Tiger asks to be removed from field duty, and completes analysis with his colleague, Bagga (Rajender Sethi), who shows him an intercepted Pakistani secret message. Tiger deduces the message was planted by Zoya, informing him of her planned arrival at an upcoming UN meeting in Istanbul.

Sometime later, Tiger and Zoya meet again at a UN Foreign Minister's Meet in Istanbul. They decide to leave everything for their love and fool their respective agencies by taken their flight to Brazil, having told their agencies that they are in Kazakhstan. Some years later, their agencies trace Zoya and Tiger to Cuba, and the ISI agents catch Zoya.

Tiger and Zoya are tracked down when they foil a mugging attempt, with video surveillance reaching RAW and ISI. After being spotted at an amateur boxing match, the couple attempt to flee Havana, but Zoya is arrested by the Cuban police and handed over to the ISI. Tiger then meets Gopi and tells him Zoya will co-operate with RAW in exchange for her escape. Tiger and Gopi lead a team to intercept Zoya's prisoner transport convoy, but Tiger and Zoya escape in a light aircraft they had stationed in a nearby field; Tiger is also non-fatally shot by Gopi. Sometime later, Tiger calls Shenoy and informs him that he and Zoya will return home when Pakistan and India no longer need ISI and RAW.

In the epilogue, several sightings of Tiger and Zoya are reported in Venice, Cape Town, Zurich, and London.