Mission: Chapter 1

Guna from Chennai learns that Sana's London surgery must be funded quickly. Unable to transfer money legally in time, he approaches a money-laundering agency for help. They hand him a symbolic ₹10 note to withdraw in the UK, starting a dangerous chain of events.

Guna flies to London with his daughter's surgery at the center of the urgency. He arranges Sana's admission to a London hospital for urgent procedure. The clock starts ticking as the family fights against time.

Thomas, a hospital staffer with a drug habit, overhears about the money-laundering and schemes to steal the token. He and his gang ambush Guna to rob him. In the ensuing struggle, Guna fights them off, but the confrontation spills into a clash with police and he is arrested for assaulting an officer.

Guna is confined in a jail cell after the arrest. He pleads with jailer Sandra James to grant a one-day leave so he can sign the documents for Sana's surgery. Sandra denies the request, keeping him in custody.

Omar Quadri, the Lashkar-e-Taiba leader, plans to attack the jail to free three imprisoned associates. He hacks into the facility's automated systems, cutting communications and unlocking cell doors. Chaos erupts as inmates riot while guards seek safety.

Using his combat skills and jail knowledge, Guna fights his way through the chaos and regains control. He collaborates with staff to stop the mass escape and discovers Omar's true objective: freeing three specific prisoners through an alternate route.

It is revealed that Guna was once a jailer in India. Days earlier, he had captured an inmate who attempted to escape and learned the man was a Lashkar operative acting on Omar's orders. This backstory explains Omar's vendetta against him.

The inmate reveals that Omar had orchestrated a bombing that killed Guna's wife and severely injured Sana, fueling his drive for vengeance. The knowledge ties Omar's operation in London to a personal vendetta and escalation of the riot. It also reveals the identities of three of Omar’s operatives in London, who are the ones Guna has now stopped from escaping.

Omar orders a mutiny in the prison kitchen to distract from the real escape. Guna again fights off attackers and saves the kitchen staff, refusing to abandon them. His resolve helps restore some order amid the chaos.

A British military helicopter on patrol spots the riot and comes under fire from Omar's militants. The army is dispatched to reinforce security and contain the escalating conflict. The siege intensifies as time runs out for Guna and Sana.

Omar kidnaps Sana from the hospital and uses her life as leverage. He demands that Guna release his men in exchange for Sana's safety. The standoff reaches a perilous peak as both sides brace for violence.

Guna agrees to the exchange, but a crossfire erupts as he confronts Omar and his team. He manages to down Omar and the remaining militants, ensuring Sana's safety and the end of the immediate threat. The operation ends with Omar neutralized.

Days later, Sana undergoes the life-saving surgery funded by the British government, and her operation succeeds. Guna awakens in the hospital to the news and is celebrated as a hero for protecting his daughter. The government honors his courage and resolve.