In London, film student Sue McKinley, Alice Patten, discovers the diary of her grandfather James, a British Army colonel who oversaw the capture and execution of Bhagat Singh, Sukhdev, and Rajguru at Lahore Jail, and writes about his quiet admiration for their revolutionary spirit even as he remains a part of the empire he serves.
Inspired by their story, Sue travels to India to make a film about the young freedom fighters. She teams up with her local associate Sonia, Soha Ali Khan, a keen student of international studies at the University of Delhi, and begins a search for actors to bring the story to life. After a string of unsuccessful auditions, she meets Sonia’s friends: Daljit “DJ” Singh, Aamir Khan; Karan Singhania, Siddharth; Sukhi Ram, Sharman Joshi; and Aslam Khan, Kunal Kapoor. Sue immediately decides to cast them in the film, with DJ as Chandra Shekhar Azad, Karan as Bhagat Singh, Aslam as Ashfaqulla Khan, and Sukhi as Shivaram Rajguru, grounding the project in the hunger for justice that the originals embodied.
The four friends are at once carefree and wary about patriotism, their futures uncertain yet tethered to the idea of a larger cause. They also clash over casting decisions when Sue drafts Laxman Pandey, a rival political figure, as Ram Prasad Bismil, a choice that strains their budding camaraderie. Still, the work begins to bond them to the project, and Sue finds herself drawn closer to DJ as their collaboration deepens into a personal relationship.
Tragedy strikes when Sonia’s fiancé, Ajay Singh Rathod, a flight lieutenant in the Indian Air Force, dies in a MiG-21 crash. The government labels the death a pilot error, but Sonia and the friends suspect something darker: evidence points to corruption, including a contract inked by Defence Minister Shashtri, Mohan Agashe, involving cheap parts for airplanes in exchange for favors. Karan is jolted to learn that his own father, Rajnath Singhania, Anupam Kher, may be implicated in the scheme.
Fueled by anger and a growing sense of purpose, the group channels their disillusionment into action. A peaceful protest at the India Gate becomes a flashpoint when the police brutalize demonstrators, leaving Ajay’s mother Aishwarya traumatized and in a coma. Laxman’s faith in his party fractures as he discovers Raghuvir Mishra’s complicity with the factions behind the crackdown, pushing him closer to the revolutionary cause.
With their ideals sharpened, the friends decide to act. They assassinate Shashtri to avenge Ajay’s death, and Karan confronts and murders Rajnath, turning the rebellion into a dramatic confrontation with the state. To ensure their message cannot be dismissed, they seize All India Radio, broadcasting a charged public statement that lays bare government corruption. The police move in, and a violent climax unfolds: Sukhi is shot, Aslam and Laxman are killed by a grenade, and DJ is gravely wounded. In the recording room, Karan and DJ share a final moment and are killed together as their message rings out.
News of the killings sparks a wave of demonstrations nationwide, and public anger swells into a chorus of resistance. Aishwarya awakens from her coma, and the film closes on Sue recounting the personal impact of meeting the boys and making the film, with the deceased appearing in a sort of afterlife, meeting a young Bhagat Singh in a peaceful, garden-like setting that hints at the enduring spirit of their struggle.
